Question

Which point is a solution to the system of linear equations?

y = −x + 6

x − 3y = 18?

A) (9,-3)

B) (6,1)

C) (1,3)

D) (-1,6)

Answer 1

A

Explanation:

y = - x + 6 → (1)

x - 3y = 18 → (2)

substitute y = - x + 6 into (2)

x - 3(- x + 6) = 18 ← distribute parenthesis and simplify left side

x + 3x - 18 = 18

4x - 18 = 18 ( add 18 to both sides )

4x = 36 ( divide both sides by 4 )

x = 9

substitute x = 9 into (1) and evaluate for y

y = - x + 6 = - 9 + 6 = - 3

solution is (9, - 3 )