Question

Solve the system of equations using addition.

4x –y = –6
5x + y = –21


What is the solution of the system?

A. (3,6)
B. (6,3)
C. (–6,–3)
D. (–3,–6)

Answer 1

4x - y = -6 ....(1)

5x + y = -21 ....(2)

(1) + (2)

9x = -27

x = -3

from (1)

4 * -3 - y = -6

we solve

y = -6

so the answer is

D ( - 3 , - 6 )