Question

What is the solution to the system of equations below?

(9, –36)
(9, 0)
(–9, 18)
(–9, –42)

Answer 1

It is A

Explanation:

Answer 2

x = 9, y = -36 → (9, -36)

Explanation:

`y=-3x-9\qquad(1)\\\\y=(1)/(3)x-39\qquad(2)\\\\\text{Substitute (1) to (2)}\\\\-3x-9=(1)/(3)x-39\qquad\text{multiply both sides by 3}\\\\-9x-27=x-117\qquad\text{add 27 to both sides}\\\\-9x=x-90\qquad\text{subtract}\ x\ \text{from both sides}\\\\-10x=-90\qquad\text{divide both sides by (-10)}\\\\x=9`

`\text{Put the value of x to (1):}\\\\y=-3(9)-9\\\\y=-27-9\\\\y=-36`