The circumference of a circle is the distance around its perimeter and equals π (approx. 3.14159) x diameter: c = π d. The area of a circle is π x (radius)² : a = π r².

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)(8ab) - (2a²)(5b)
(5 x 8)(a x a x b) - (2 x 5)(a² x b)
(40)(a¹⁺¹ x b) - (10)(a²b)
40a²b - 10a²b
30a²b

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

a = ½bh
a = ½ x 6 x 8 = \( \frac{48}{2} \) = 24

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.

To solve this equation, repeatedly do the same thing to both sides of the equation until the variable is isolated on one side of the < sign and the answer on the other.

-6c + 9 < \( \frac{c}{-1} \)
-1 x (-6c + 9) < c
(-1 x -6c) + (-1 x 9) < c
6c - 9 < c
6c - 9 - c < 0
6c - c < 9
5c < 9
c < \( \frac{9}{5} \)
c < 1\(\frac{4}{5}\)