SOLUTION: find the solution to each system by the substitution method 3x-5y=7 x-4y= -7

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Question 717676: find the solution to each system by the substitution method 3x-5y=7 x-4y= -7
Answer by checkley79(3341) About Me  (Show Source):
You can put this solution on YOUR website!
3x-5y=7
x-4y= -7
x=4y-7 replace x with (4y-7) in the first equation & solve for y.
3(4y-7)-5y=7
12y-21-5y=7
7y=7+21
7y=28
y=28/7
y=4 ans.
x=4*4-7
x=16-7
x=9 ans.
Proof:
3*9-5*4=7
27-20=7
7=7