Work shown: x-y=5 —-> subtract x from both sides to give you y alone. -y= -x+5 —-> next step is to continue to get y alone so you have to divide both sides by -1. y=x-5 now the first one is done x+y=-10 —-> solve to get y alone so subtract both sides by x making it y=-x-10 Meaning that the two lines are perpendicular to each other.
