Hello,

I am trying to solve this equation:

7x + 3y = 12

3x + 7y = 6

If x and y satisfy the system of equations above, what is the value of x-y?

I have tried really hard to solve this, I am appalling bad at Math ! Any help would be appreciated..

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- Jan 4th 2013, 11:29 AM #1

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- Jan 4th 2013, 11:35 AM #2
## Re: Help !

Using elimination, we could multiply the first equation by 3 and the second by -7 to get:

$\displaystyle 21x+9y=36$

$\displaystyle -21x-49y=-42$

Now, add the equations to eliminate*x*, and then solve for*y*. Then plug in this value for*y*into either original equation to find*x*.

What do you find?

- Jan 4th 2013, 11:50 AM #3

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- Jan 4th 2013, 12:04 PM #4

- Jan 4th 2013, 12:13 PM #5

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