SOLUTION: can u help me with this with simple step by step instructions: 3x+y=5 y=x-7

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Question 193856: can u help me with this with simple step by step instructions:
3x+y=5
y=x-7
Answer by edjones(8007) About Me  (Show Source):
You can put this solution on YOUR website!
3x+y=5
y=x-7
.
3x+(x-7)=5 substitute x-7 for y
3x+x-7=5
4x=12
x=3
y=-4
.
Ed