How to substitute equations for solutions 3x-2y=9 Y=2x-7

2 answers:

7 0

First I would rewrite it so all the x's and y's are in the same places

3x-2y=9
-2x+y=-7

Then multiply the bottom one by 2
-4x+2y=-14

Then add the equations
3x-2y=9
+-4x+2y=-14
-------------------
-x=-5 or x=5

The substitute this into one of the original equations to solve for y.

y=2(5)-7
y=3

So your answer is x=5 and y=3 or (5,3)

Hope this helps.

xxTIMURxx [149]3 years ago

5 0

3X-2(2X-7)=9

3X-4X+14=9

-X=-5

X=5

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