10 POINTs!! Please give some sort of explanation

Could somebody me with this radical simplification?

Aline is perpendicular to another line m2= (-1/m1), where m1 is the slope of the original line and m2 is the slope of the perpendicular line. which of the following equations represents the line that passes through the point (-2,1) and is perpendicular to the line below?

Solve the system of equations. 2x-2y=-4 and x+y=8. show work