8x-3y = -21, 3x + y = -10; Prove: x = -3

Question

asked Jun 13, 2024 78.4k views

1 Answer

Mfaerevaag · Answer 1 · 2024-06-18T15:05:32+0000

Answer:

We can prove x = -3 by plugging in 3 for x for each equation and show that each equation yields the same:

8x - 3y = -21

$8(-3)-3y=-21\\-24-3y=-21\\-3y=3\\y=-1$

3x + y = -10

$3(-3)+y=-10\\-9+y=-10\\y=-1$

Because we plugged in x for each equation and got the same result for y, this proves that x = -3 is a solution to the system of equations.