The graph of line R is shown below. Which equation describes a line perpendicular to line R that passes through the point (3, -6)?
A x - 3y=21
B. 3x + y =3
C. 3x - y =15
D.3x - y = 3

Could somebody me with this radical simplification?

Look at the figure below: triangle abc is a right triangle with angle abc equal to 90 degrees. the length of ac is 5 units and the length of ab is 4 units. d is a point above c. triangle adc is a right triangle with angle dac equal to 90 degrees and dc parallel to ab. what is the length, in units, of segment cd?

Using elimination, what is -4x+2y=-12 4x+8y=-24