SOLUTION: Im working on solving linear equations by elimination. whats 2x+5y=12 and -4x+4y=18

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Question 695908: Im working on solving linear equations by elimination.
whats 2x+5y=12 and -4x+4y=18
Answer by Stitch(470) About Me  (Show Source):
You can put this solution on YOUR website!
Given: 2X+%2B+5Y+=+12 and -4X+%2B+4Y+=+18
Start by setting the equations equal to zero.
2X+%2B+5Y+-+12+=+0 and -4X+%2B+4Y+-+18+=+0
Multiply the first equation by -2
-4X+-+10Y+%2B+24+=+0
Since both eqautions are equal to zero, you can set them equal to each other.
-4X+-+10Y+%2B+24+=+-4X+%2B+4Y+-+18
Add 4X to both sides
-10Y+%2B+24+=+4Y+-+18
Add 10Y to both sides
24+=+14Y+-+18
Add 18 to both sides
42+=+14Y
Divide both sides by 14
highlight%283+=+Y%29
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Now plug 3 into one of the given equations for Y
2X+%2B+5Y+=+12
2X+%2B+5%2A%283%29+=+12
2X+%2B+15+=+12
Subtract 15 from both sides
2X+=+-3
Divide both sides by 2
highlight_green%28-1.5+=+X%29