Your using the distributive property in your example, hope that helps.
3x+y=−11
3x+y+−3x=−11+−3x(Add -3x to both sides)
y=−3x−11
2x+2y=−10
2x+2(−3x−11)=−10
−4x−22=−10(Simplify both sides of the equation)
−4x−22+22=−10+22(Add 22 to both sides)
−4x=12
−4x
−4
=
12
−4
(Divide both sides by -4)
x=−3
y=−3x−11
y=(−3)(−3)−11
y=−2(Simplify both sides of the equation)
Answer:
x=−3 and y=−2
D.(-3,-2)