Solve by elimination. x+9y=-49 and 9x+8y=-76

Question

Solve by elimination.

Answer 1

Elimination method

x+9y = -49

Multiple to each side by 9.

9x+81y = -441 ---------> (1)

9x+8y = -76 --------> (2)

To eliminate the x value, subtract equation (2) from (1).

9x+81y = -441

9x+8y = -76

(-)  (-)    (+)

___________

73y = -365

Divide to each side by 73.

73y/73 = -365/73

⇒ y = -5

Substitute the y value in (2).

9x+8*-5 = -76

9x-40 = -76

Add 40 to each side.

9x-40+40 = -76+40

9x = -36

Divide to each side by 9.

9x/9 = -36/9

⇒ x = -4

Solution x = -4, y = -5.