Question

18. Which ordered pair is a solution of the system of linear equations listed below?

2x + y = -5
-x+3y=6
A. (-3, 1)
B. (3, 1)
C. (-3,-1)
D. (-1,3)​

Answer 1

A

Explanation:

Given the 2 equations

2x + y = - 5 → (1)

- x + 3y = 6 → (2)

Multiplying (2) by 2 and adding to (1) will eliminate the x- term

- 2x + 6y = 12 → (3)

Add (1) and (3) term by term to eliminate x

0 + 7y = 7

7y = 7 ( divide both sides by 7 )

y = 1

Substitute y = 1 into either of the 2 equations and solve for x

Substituting into (1)

2x + 1 = - 5 ( subtract 1 from both sides )

2x = - 6 ( divide both sides by 2 )

x = - 3

solution is (- 3, 1 ) → A