The radius of a cylindrical gift box is (2x+3 ) inches. The height of the gift box is twice the radius. What is the surface area of the cylinder?

Since the surface area formula is 2πrh+2πr², we can plug 2x+3 in for r and 2 * (2x+3) = 4x+6 in for h to get 2π (2x+3) (2) (2x+3) + 2π (2x+3) ²=4π (2x+3) ²+2π (2x+3) ²=2π (2x+3) ² (2+1) = 6π (2x+3) ²

=6π (4x²+12x+9)