If r = 8 units and x = 8 units, then what is the total surface area of the cylinder shown above?

The surface area of a cylinder is the area of the top and bottom circle and the side of the cylinder, which is really a rectangle with the circumference of the circle for the length and x for the width.
So the formula is 
Plug in r  and x into the equation;



which is about 804.25 square units since it is an area.
Hope this helps. 

Basic algebra equation. first set up your equation: divide out 9.and now you are left with 2x + 4 = 8.