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.

(9a)(4ab) + (8a²)(3b)
(9 x 4)(a x a x b) + (8 x 3)(a² x b)
(36)(a¹⁺¹ x b) + (24)(a²b)
36a²b + 24a²b
60a²b

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.

(5a)(6ab) - (6a²)(2b)
(5 x 6)(a x a x b) - (6 x 2)(a² x b)
(30)(a¹⁺¹ x b) - (12)(a²b)
30a²b - 12a²b
18a²b

A rectangle is a parallelogram containing four right angles. Opposite sides (a = c, b = d) are equal and the perimeter is the sum of the lengths of all sides (a + b + c + d) or, comonly, 2 x length x width. The area of a rectangle is length x width. A square is a rectangle with four equal length sides. The perimeter of a square is 4 x length of one side (4s) and the area is the length of one side squared (s²).

A rhombus is a parallelogram with four equal-length sides. A square is a rectangle with four equal-length sides.

The area of a triangle is equal to ½ base x height:

a = ½bh
a = ½ x 7 x 6 = \( \frac{42}{2} \) = 21