Question

4. The radius of a cylinder is 3x – 2 cm. The height of the cylinder is x + 3 cm. What is the surface area of the cylinder? Use the formula A = 2r2 + 2rh.
Answer: 2 pie (12x^2 -5x -2) or just D

Answer 1

D is your answer. For the entire quick check its.
A-D-B-D-C
100% correct

Answer 2

Answer: $(24\pi x^2 - 10\pi x - 4\pi)$ square centimeters

Explanation:

Let

$r = \text{radius of the cylinder} = 3x - 2 \newline \indent h = \text{height of the cylinder} = x + 3$ 

Then the surface area of the cylinder is given by

$A = 2\pi r^2 + 2\pi rh \newline \indent = 2\pi r (r+h) \newline \indent = 2\pi (3x - 2) (\left ( 3x - 2 \right ) +\left (x + 3 \right )) \newline \indent = 2\pi (3x - 2) (4x + 1) \newline \indent = 2\pi (12x^2 - 5x - 2) \newline \indent \boxed{A = (24\pi x^2 - 10\pi x - 4\pi)cm^2}$