Question

Solve the system using elimination.

x − 4y = 4
3x − 4y = −12

A. (−2,112)

B. (−8,−3)

C. (−8,9)

D. (−2,−112)

Answer 1

B

Explanation:

x - 4y = 4 → (1)

3x - 4y = - 12 → (2)

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

- x + 4y = - 4 → (3)

Add (2) and (3) term by term to eliminate y

2x + 0 = - 16

2x = - 16 ( divide both sides by 2 )

x = - 8

Substitute x = - 8 into either of the 2 equations and solve for y

Substituting into (1)

- 8 - 4y = 4 ( add 8 to both sides )

- 4y = 12 ( divide both sides by - 4 )

y = - 3

solution is (- 8, - 3 ) → B

Answer 2

B. (-3,-8)

Explanation:

I have aced tests on these. You can trust this is correct - plus it's verified by a calculator.