Question 256592
Here the addition method means subtract 6x+5y=-35 or add -(6x+5y=-35) 
6x+15y=-45
6x+5y=-35
6x-6x=0
15y-5y=10y
-45-(-35)=-10
10y=-10
y=-1
plug 1 for y in either equation
6x+5y=-35
6x-5=-35
add 5
6x=-30
x=-5
(-5,-1)