Question

(3) x + y = 0 ; 2x - y = 9​

Answer 1

Step-by-step explanation:

x+y=0

x=-y

therefore, 2x - y= 9

2(-y) -y=9

-2y-y=9

-3y=9

y=9/-3

y= -3

so, x+y=0

x-3=0

x= 3