To multiply monomials, multiply the coefficients (the numbers that come before the variables) of each term, add the exponents of like variables, and multiply the different variables together.

(2a)(4ab) + (6a²)(4b)
(2 x 4)(a x a x b) + (6 x 4)(a² x b)
(8)(a¹⁺¹ x b) + (24)(a²b)
8a²b + 24a²b
32a²b

The surface area of a cube is (2 x length x width) + (2 x width x height) + (2 x length x height):

sa = 2lw + 2wh + 2lh
sa = (2 x 8 x 5) + (2 x 5 x 5) + (2 x 8 x 5)
sa = (80) + (50) + (80)
sa = 210

To multiply binomials, use the FOIL method. FOIL stands for First, Outside, Inside, Last and refers to the position of each term in the parentheses.

The surface area of a cylinder is 2πr² + 2πrh:

sa = 2πr² + 2πrh
sa = 2π(9²) + 2π(9 x 9)
sa = 2π(81) + 2π(81)
sa = (2 x 81)π + (2 x 81)π
sa = 162π + 162π
sa = 324π

To factor a quadratic expression, apply the FOIL (First, Outside, Inside, Last) method in reverse.