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.

(4a)(2ab) + (8a²)(4b)
(4 x 2)(a x a x b) + (8 x 4)(a² x b)
(8)(a¹⁺¹ x b) + (32)(a²b)
8a²b + 32a²b
40a²b

A cube is a rectangular solid box with a height (h), length (l), and width (w). The volume is h x l x w and the surface area is 2lw x 2wh + 2lh.

A circle is a figure in which each point around its perimeter is an equal distance from the center. The radius of a circle is the distance between the center and any point along its perimeter. A chord is a line segment that connects any two points along its perimeter. The diameter of a circle is the length of a chord that passes through the center of the circle and equals twice the circle's radius (2r).

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 1 x 5) + (2 x 5 x 9) + (2 x 1 x 9)
sa = (10) + (90) + (18)
sa = 118

The perimeter of a triangle is the sum of the lengths of its sides:

p = x + y + z
p = 14cm + 14cm + 10cm = 38cm