The first step to solve a quadratic equation that's set to zero is to factor the quadratic equation:

c² - 64 = 0
(c - 8)(c + 8) = 0

For this expression to be true, the left side of the expression must equal zero. Therefore, either (c - 8) or (c + 8) must equal zero:

If (c - 8) = 0, c must equal 8
If (c + 8) = 0, c must equal -8

So the solution is that c = 8 or -8

You can only add or subtract monomials that have the same variable and the same exponent. For example, 2a + 4a = 6a and 4a² - a² = 3a² but 2a + 4b and 7a - 3b cannot be combined. However, you can multiply and divide monomials with unlike terms. For example, 2a x 6b = 12ab.

To multiply binomials, use the FOIL method. FOIL stands for First, Outside, Inside, Last and refers to the position of each term in the parentheses.

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).

An equation is two expressions separated by an equal sign. The key to solving equations is to repeatedly do the same thing to both sides of the equation until the variable is isolated on one side of the equal sign and the answer on the other.