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Post by *~Crazyleo~* on Oct 11, 2006 14:39:21 GMT -5
Substituting Equations, Personally I'm learning about this in College Math 025, but feel free to discuss it from a different course as well....
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Post by *~Crazyleo~* on Oct 11, 2006 14:40:39 GMT -5
Okay so Im at the end of my home work and i get the following problem:
The Difference between two numbers is 16. Three times the larger number is seven times the smaller. What are the numbers?
I cant figure it out for the life of me, maybe im just not seeing it....
PLEASE HELP!!
Oh and I have the answer i just need to find out how to get them...Ive been trying all day
Thanks
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Post by Tyual on Oct 11, 2006 19:24:13 GMT -5
Okay, now I can't swear to this, butttt, I believe we'll set this up in 2 equations. So lets say this:
x - y = 16 (Difference of 2 numbers = 16.) and
3x = 7y
So lets solve for X and substitute in. I'll solve the top one and substitute it into the bottom. You can do the bottom and substitute into the top if you want. So solving the top equation for X will give you:
x = y + 16
Plug this in for X in 3x = 7y and we get:
3 ( y + 16) = 7y.....gives us:
3y + 48 = 7y
Simplify and get:
48 = 4y.
y = 12.
so lets take Y and put it in our original equation, x + y = 16.
x + 12 = 16.
x = 4.
So your answer is x =4 and y = 7.
At least, I -THINK- that's right....If not, well I tried to help!
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Post by *~Crazyleo~* on Oct 15, 2006 13:52:21 GMT -5
see thats what i kept getting, but the answer is x=12 y=28, and i still dont see how they set it up....
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Post by Tyual on Oct 15, 2006 15:45:40 GMT -5
What the heck? I'd make them show you how the did that, then please tell me too, lol.
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Post by *~Crazyleo~* on Oct 16, 2006 17:19:06 GMT -5
Elmo says that you added the x+y instead of subtracting....i think that solves it correctly
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Post by Tyual on Oct 16, 2006 20:56:08 GMT -5
whoops! in the very end I did, but at the beginning of the problem set up, I had it as subtraction!
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Post by wowposter on Sept 4, 2008 23:36:38 GMT -5
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Post by wowposter on Sept 10, 2008 6:05:01 GMT -5
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Post by wowpower on Sept 15, 2008 7:00:01 GMT -5
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Post by wowpower on Sept 17, 2008 2:30:24 GMT -5
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