Question

Solve system of equations by elimination
Solve x + 3y = 9
3x - 3y = -13

Answer 1

Since the coefficient on the y-variables are opposites, we make linear combination of the two equations
x + 3y = 9
3x - 3y = -13
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4x =-4
x=-1
Now sub x=-1 into either of the given equations to find y
-1+3y=9
3y=10
y=10/3
Solution may be written (10/3, -1) or simple as
x=10/3, y=10/3