9514 1404 393
Answer:
(5, -5)
Step-by-step explanation:
I like a graphing calculator for quickly finding a solution to a system of equations. It shows the solution to be (5, -5).
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We can add the second equation to 2 times the first to eliminate the y-variable.
2(-7x -3y) +(3x +6y) = 2(-20) +(-15)
-11x = -55 . . . . . collect terms
x = 5 . . . . . . . . . divide by -11
Substituting this value into the second equation, we have ...
3(5) +6y = -15
6y = -30 . . . . . . . . subtract 15
y = -5 . . . . . . . . . . divide by 6
The solution is (x, y) = (5, -5).
