Answer:
y=-5,x=2
Step-by-step explanation:
3x+3y=-9________________eqn 1
3x-3y=21________________eqn 2
using elimination method
3x+3y=-9
-
3x-3y=21
subtract equation 2 from equation 1
0+6y=-30
6y=-30
y=-30/6
y=-5
substitute the value of y in equation 1
3x+3y=-9
3x+3(-5)=-9
3x-15=-9
3x=-9+15
3x=6
x=6/3
x=2
