SOLUTION: y=2x x+y=12

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Question 68734: y=2x
x+y=12
Answer by tutorcecilia(2144) About Me  (Show Source):
You can put this solution on YOUR website!
y=2x
x+y=12
.
.
y=2x
x+y=12 [solve for y so that both equations match]
y=-x+12
.
y=2x
(2)(y=-x+12) [multiply by a number that will cause the cancellation of a variable]
.
1y=2x
2y=-2x+24
_________
3y=24 [solve for y]
.
3y/3=24/3
y=8
.
Solve for x
y=2x [let y=8]
8=2x
8/2=2x/2
4=x
.
check by plugging x=4 and y=8 back into the original equations
y=2x
8=2(4)
8=8 [checks out]
.
x+y=12
(4)+(8)=12
12=12 [also checks out]