Answer:
(x, y) = (-4, -4)
Step-by-step explanation:
The coefficients of x will be the same if we multiply the first equation by 3:
-9x +21y = -48
Now, we can solve the system by subtracting the second equation. Since the coefficients of x are the same, the subtraction eliminates x from the equation.
(-9x +21y) - (-9x +5y) = (-48) - (16)
16y = -64 . . . . . . simplify
y = -4 . . . . . . . . . divide by 16
Substituting this value into the first equation, we get ...
-3x +7(-4) = -16
-3x = 12 . . . . . . . add 28
x = -4 . . . . . . . . . divide by -3
___
Check
This solution is confirmed by a graphing calculator.
