Question 331756
5x+5y=-30 
divide by 5
x+y=-6
y= -6-x
..
and 2x-y=15
plug the value of y in the equation
2x-(-6-x)=15
2x+6+x=15
3x+6=15
3x=15-6
3x=9
x=3
..
plug value of x in the equation x+y=-6
3+y=-6
y=-6-3
y=-9