L O.

# how do you solve 4x - y = 5 and 4x + 4y =-4 using elimination

Please solve the linear system using elimination.

4x - y = 5
4x + 4y = -4

Thanks

## 3 Answers By Expert Tutors

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Mathematics professor at Community Colleges

L O.

I am confused.  If  I put 3 for y then the first equation I get 2 for x.  4(2) - 3 = 5.  But when I use the same for the 2nd equation, it doesn't work.  I get a positive 4 for the answer.

-4(2) + 4(3) = 4.   Equation 2's answer is a -4.
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12/27/13 Paul H.

Actually, this one was done in a heap of hurry. The SECOND equation should have been written as

-4x -4y = +4

Then when you add I and II together, you get -5y = 9  or y = - 9/5
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12/27/13 Parviz F.

You have to Substitute in :4X + 4y = -4

The whole 2nd equation was multiplied   by -1 to subtracted from the first equation.
You used substitution by only multiplying the first term 4X by -1.
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12/27/13

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