-6x-2y=42
x-y=-15
Multiply x-y=-15 by 6 ( eliminate the x first)
6(x-y)=6(-15)
(6)(x)=6x
(6)(-y)=-6y
6(-15)=-90
-6x-2y=42
6x-6y=-90
eliminate x the systems of equations by subtracting
-6x+6x-2y+-6y=42-90
-2y-6y=42-90
-8y=-48
divide both sides by -8 to get y by itself
-8y/-8=-48/8
y=6
Find x by substitution method
use y=6 into one of the system of equations
x-y=-15
x-6=-15
move -6 to the other side
sign changes from -6 to +6
x-6+6=-15+6
x=-15+6
x=-9
answer:
(-9,6)
