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)(7ab) + (5a²)(4b)
(5 x 7)(a x a x b) + (5 x 4)(a² x b)
(35)(a¹⁺¹ x b) + (20)(a²b)
35a²b + 20a²b
55a²b

To combine like terms, add or subtract the coefficients (the numbers that come before the variables) of terms that have the same variable raised to the same exponent.

6a - 6a = 0a

The formula for circumference is circle diameter x π. Circle diameter is 2 x radius:

c = πd
c = π(2 * r)
c = π(2 * 8)
c = 16π

The area of a trapezoid is one-half the sum of the lengths of the parallel sides multiplied by the height:

a = ½(b + d)(h)
a = ½(3 + 5)(3)
a = ½(8)(3)
a = ½(24) = \( \frac{24}{2} \)
a = 12

The coordinate grid is composed of a horizontal x-axis and a vertical y-axis. The center of the grid, where the x-axis and y-axis meet, is called the origin.