I Promised No More Math, But….
computing September 20th, 2009
I don’t know why my family keeps sending me math questions to answer. Despite my protests that I don’t do math, my niece Amy sent me this equation and asked if I knew how to solve it.
x (.23) = x – 10
She actually knows the value of “x” because a site called Wolfram Alpha lets you enter all kinds of equations and it’ll give you the answer. If you want to compute the eigenvalues and eigenvectors of a matrix, head over there and check it out. Then shoot yourself because no one should want to know the eigen-anything of anything.
I suspect my niece hangs out at this site for fun, since she once took a college physics course for its entertainment value. I don’t know how she’s related to me. Me no do school for fun.
Anyway, Wolfram solves for “x,” but doesn’t tell you how to arrive at the answer.
There’s a Junk Drawer magnet and a pat on the head for anyone who can explain the method to find “x.”
Remember to show your work.
Go!
Stumble it!
September 21st, 2009 at 2:58 pm
Wouldn’t it be something like:
x(.23) = x-10
Then you get both X’s on one side
.23 = 2x – 10
Add 10 to both sides.
10.23 = 2x
Divide by 2.
5.115 = x.
I’m not sure if that’s right, but hey, that’s the type of stuff I’m learning in school. :/
September 21st, 2009 at 3:09 pm
You really know how to make a guy look bad!
September 21st, 2009 at 4:48 pm
ann — See now, if they would have just built calculators with an “x” button, how much less we’d all be annoyed with math. Little secret — my husband does our checkbook. If I did it, well, you can just guess.
Dede — All I know is what 1x means. Seems I’ve gotten dumber since my last algebra post.
CatLadyLarew — Oh, bless your heart teaching kindergarteners. I’m guessing you are exhausted at the end of every day. All those monkeys to count!
JD at I Do Things — Another secret — I was always asked to clap erasers outside because I was one of the most trustworthy kids in class. Ha! So no one explained to us what an eigenvector was. I’m thankful. Aren’t you?
Steve — I’m telling you, it’s he damn x thing on the left that gives me a migraine. I never thought you could just cancel them out like that. This equation really bothers me, but thanks for your solution.
Shieldmaiden1196 — What a fond memory. Wait. It was fond, right?
Jeff — My apologies, Jeff. Even if I’m tempted in the future, there will be no more “solve for x” directives. I’m done with math!
Jenn Thorson — Would you believe I got through college without needing to take statistics? I don’t know how I pulled that off. Everyone was mad at me for missing it. Then again, I had calculus and they didn’t, so I called it even.
mytheory — Yes, and congrats!
Trade Show Guru Steve — Did you just cheat?
Chris at TheSnackHound — That’s why multiple choice tests were so awesome. You had a 25% chance of getting something right at least.
Wendy — You did! And of all the explanations, I still had to mull over the so-called easier ones for a bit of time. I’m hopeless.
Hospedagem — I like how you did that. In fact, I think that’s how I approached it in the beginning, but still didn’t get it. Sigh.
Grace — The .77 comes from the difference between 1.0 and .23, if that’s any help at all. But don’t sweat it. We’re all in pain over this.
Chris at Maugeritaville — The decimal fooled me.
Karen — I don’t have use for it either. That’s what WolframAlpha is for, apparently. Thank God for that.
Geakz — Wouldn’t surprise me.
Regan — Close, but no cigar.
Document Scanning Services — Get in line behind me.
September 21st, 2009 at 7:50 pm
It’s quite simple. You compute the ratio for the undulating hypothesis times the balance of the weight of 3 bananas versus the total amount of time it takes to find a set of keys you threw into the dumpster instead of the trash you had in your other hand.
Do I win??
.-= kathryn´s last blog ..Say It Again =-.
September 21st, 2009 at 9:15 pm
.23x=x-10
+10 +10
10+2.3x=x
-2.3x -2.3x
10=-1.3x
/1.3
x=7.692307692307 repeating
September 21st, 2009 at 9:20 pm
Clapping erasers sounds like fun. At our arithmetic (as it was called) lesson the teacher wrote an example out and told us to get on with our lesson. I asked how he had done a particular part of it and his answer? “If you didn’t understand it the first time, put your head down and go to sleep” He was NOT joking. He refused to explain anything a second time. I HATED arithmetic lessons!
September 21st, 2009 at 10:03 pm
Already got a magnet!
Na na na na nah!!!
: D
.-= Ferd´s last blog ..Midtown Café & dessertery =-.
September 21st, 2009 at 10:12 pm
I got a 46% on my simple math exam in high school guess I can’t help although I’ve always wanted to know more.
Dorothy from grammology
grammology.com
.-= Dorothy Stahlnecker´s last blog ..Vacations can be exhausting =-.
September 22nd, 2009 at 12:05 am
x(.23)= x-10
Isolate x on one side of the equation- aka- subtract x from both sides:
x(.23)-x= -10
This can also be written as .23x-1x=-10
.23x-1x= -.77x
-.77x=-10
Divide both sides by -.77
x= -10/-.77
x= 12.987
Check your work by plugging in 12.997 for x.
Work checks out!
(That was actually kind of fun)
.-= Jennifer Landsberger´s last blog ..#6 on the "Top Ten Countdown" =-.
September 22nd, 2009 at 3:06 am
Hey Kathy!
Remember that post you did a while ago on “blog stalkers?” Yeah, I read it, then left without commenting. And then you go and put a math problem on here…can’t…resist…must…solve…
So I read through all the responses and I agree most with comment #13 from Kathy, only because the answer is in fraction form which is more accurate. The question didn’t specify to how many decimal places the answer should be in, so my instinct would be to keep it in a fraction, the most accurate form. This is how:
x(.23)=x-10
.23x=x-10
Now, get rid of the decimal by multiplying both sides by 100, like so:
100(.23x)=100(x-10)
distribute…
23x=100x-1000
(isn’t it much nicer dealing with whole numbers?)Now subtract 100x from each side…
23x-100x=100x-100x-1000
-77x=-1000
divide both sides by -77 to isolate x…
x=-1000/-77
the negatives cancel, so you are left with
x=1000/77
In decimals, that would be 12.98701299 or maybe something even longer- I’m limited by my calculator’s display window length. This may seem like splitting hairs but it could make the difference if this equation were pivotal in launching a rocket to Mars. Or something like that. So there you have it, one of your stalkers is exposed, and she is a geek.
.-= Emily´s last blog ..One Year =-.
September 22nd, 2009 at 5:06 am
kathryn — Yes, that’s correct. So did you dumpster dive to retrieve the bananas? Fruit is so expensive these days.
Karen — Um, no. Not according to WolframAlpha, nor all the smartie pants people above you.
Babs Beetle — It is fun, mostly because if you get picked to do it you are a teacher’s pet and that makes you special. It’s no wonder you didn’t like arithmetic. Your teacher was mean and possibly the worst teacher to walk the planet. How you supposed to learn anything that way?
Ferd — Dude! And I believe that’s “Neener neener neeeeeener!”
Dorothy Stahlnecker — Well, you won’t get any better here. More than half of us have no idea either.
Jennifer Landsberger — See, this is the part I get stuck on, and I don’t know why my brain just wouldn’t have thought of that: “This can also be written as .23x-1x=-10
.23x-1x= -.77x.” I like your approach. It looks the easiest.
Emily — OK, so the only way you’re going to comment is if I put math on the blog? You realize how mad that’s gonna make everybody, right? I was going to ask if you are a nerd, asking about decimal places, but then I see you already admitted you’re a geek. Close enough.
September 22nd, 2009 at 5:20 am
What the F Kathy? Writers don’t do math.
(Head explodes and brain matter litters the monitor and keyboard. Mr. C yells from the basement, “What was that noise?”)
.-= cardiogirl´s last blog ..If we’re gonna be friends, don’t close your eyes and raise your eyebrows when you answer my questions =-.
September 22nd, 2009 at 9:01 am
Math? Phooey!
.-= The Hawg!´s last blog ..Yay for The Boy! =-.
September 22nd, 2009 at 9:02 am
Most ironic part of post for me: “If you enjoyed this post, make sure you subscribe to my RSS feed!” If I weren’t already a subscriber, I’d run away, quickly. 🙂
.-= unfinishedrambler´s last blog ..Agatha Christie In Music: Sublime? …er…well, not always =-.
September 22nd, 2009 at 10:23 am
I got it right, really I did.
.-= carol at A Second Cup´s last blog ..The Magic of HomeMade Bread: A Second Cup Recipe Suggestion =-.
September 22nd, 2009 at 12:55 pm
I’m leaving this post and I’m taking my ball with me!
.-= Bobbi´s last blog ..My Dog the Rock Star =-.
September 22nd, 2009 at 1:19 pm
My 13 yo homeschooled son says:
x(.23)=x-10
.23x-x=-10 (restate)
-.77x=-10 (subtract x from both sides)
x=12.987 (divide both sides by -.77)
He says this is 7th grade math.
September 22nd, 2009 at 1:23 pm
DH was thrilled you stopped by his new website. 🙂
.-= pussreboots´s last blog ..Review: The Case of the Climbing Cat =-.
September 22nd, 2009 at 3:45 pm
You lost me at eigenvalues… erf.
September 22nd, 2009 at 5:27 pm
Okey doke… It’s really simple algebra, which is NOT an oxymoron. (George Bush was an oxymoron.) Anyhoo…
x(.23)=x-10
Now add 10 to each side to isolate x. (Awww… Poor x.)
That gives you
.23x+10=x
Now you subtract .23x to each side and get
10=x-.23x which is just like saying 10= .77x
Now you divide each side by .77 (isolating x for real this time) and get x=10 divided by .77 which is 12.987
I’m taking my bow now! Sorry– I’m the ultimate nerd.
.-= Leah Rubin´s last blog ..In Case You Missed It =-.
September 22nd, 2009 at 6:03 pm
The other day I pulled a stupid and had to redo my blog. If my last posts are not showing up in my feed please come back and re-subscribe. thanks
.-= grannyann´s last blog ..A Dogs Prayer =-.
September 22nd, 2009 at 7:08 pm
Oh man! and this is a humor blog… I blame the politicians in Washington for making the general populace so humorless that we are now blogging about math.
Carry on… ;0P
.-= Michelle Gartner´s last blog ..Hometown Story ~ An Early Marilyn Monroe Film =-.
September 23rd, 2009 at 4:30 am
Cardiogirl — I’m sorry. You’re right. Point noted. Swear, no more math!
The Hawg! — Says you, me and mostly everyone else.
unfinishedrambler — Ha! I would too. Not a whole lot of enjoyment here, except for the math experts in the crowd.
carol at A Second Cup — I believe you.
Bobbi — I deserved that.
The Mother — It may be 7th grade math, but you can tell how long half the people here have been out of 7th grade.
pussreboots — I’m bummed because you’re on Pacific coast time and I’ll probably never get there when stuff is happening, but I want to, because it sounds like a blast and I just might learn something.
Heidi at trulyengaging — I didn’t even bother looking those words up, and I’m still not!
Leah Rubin — Funny! Yeah, poor “x,” no one ever knowing who he is and always isolating him. Of course, he has good company with “y” in certain equations. So there’s that. Thanks for playing!
grannyann — I see your posts, but when I click Home, I get an error (jut an FYI).
Michelle Gartner — Actually, you can blame writer’s block in this case.
September 23rd, 2009 at 8:27 am
x = .23x + 10
x + 10 = .23x
.23x – x = 10
-.77x = 10
x = – 10/.77
x = -12.99
.-= honeypiehorse´s last blog ..Who do you trust? =-.
September 23rd, 2009 at 8:56 am
OMG!!!!! MATH!!!! Looking at that equation took me back to my 11th grade Trig class….not a place I wanted to be this morning.
.-= Roschelle´s last blog ..Becoming a Pro Blogger =-.
September 23rd, 2009 at 11:46 am
Not adding to the sums – but it is so strange that we speak the same language and yet in Britain it is always referred to as mathematics or maths. First school tend to use the word sums.
.-= Polly´s last blog ..World population =-.
September 23rd, 2009 at 11:51 am
Now this is the most original way I’ve seen to get people to do your homework..
September 23rd, 2009 at 2:21 pm
.23x – x-10
.23x -x = -10
-.77x = -10
divide both equation by -.77
then x= 12.99
i bet some has d same answer with me, this is the correct one!!!
.-= Chip´s last blog ..I’m having a Credit Crunch! =-.
September 23rd, 2009 at 8:28 pm
The approach taken by Kathy is the correct on e and the result is just: x=1000/77
Please do not try to compute it unless you are in a Physics class where you need an approximate value.
.-= WordPress Blog Design´s last blog ..Upgrading to WordPress 2.8 Problems =-.
September 23rd, 2009 at 10:55 pm
I’d give it a go, Kathy, but I can’t stop laughing at cardiogirl’s comment.
And I lied…I wouldn’t give it a go…I suck bean curd cakes when it comes to numbers. Argh.
.-= earthtoholly´s last blog ..Black Acorn =-.
September 28th, 2009 at 12:05 pm
Does it have anything to do with the X-Factor?
October 1st, 2009 at 3:19 am
Maths Maths Maths!!
I aced it in school every year. Loved Geometry class!
October 2nd, 2009 at 1:55 pm
You have to be kidding! Like you, math and I aren’t friends. We aren’t even on speaking terms. After 5th grade, I can’t help my children with math homework. Baby girl is now in the 5th grade, and her time is just about up!
.-= LaTonya´s last blog ..I Don’t Run =-.
October 28th, 2009 at 5:24 pm
It finds the line for the equation (kinda complicated) and uses this to work it out. Sorry to be so vague.
.-= alex´s last blog ..Top 15 ways of building backlinks =-.