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 area of a parallelogram is equal to its length x width:

a = l x w
a = a x b
a = 8 x 5
a = 40

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 x 7b = (5 x 7) (a x b) = 35ab

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.

2a⁷ - 6a⁷ = -4a⁷

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.

-6b - 3 > \( \frac{b}{-3} \)
-3 x (-6b - 3) > b
(-3 x -6b) + (-3 x -3) > b
18b + 9 > b
18b + 9 - b > 0
18b - b > -9
17b > -9
b > \( \frac{-9}{17} \)
b > -\(\frac{9}{17}\)