To factor a quadratic expression, apply the FOIL (First, Outside, Inside, Last) method in reverse.

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

x² + 15x + 54 = 0
(x + 6)(x + 9) = 0

For this expression to be true, the left side of the expression must equal zero. Therefore, either (x + 6) or (x + 9) must equal zero:

If (x + 6) = 0, x must equal -6
If (x + 9) = 0, x must equal -9

So the solution is that x = -6 or -9

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 equal sign and the answer on the other.

4z + 5 = \( \frac{z}{-4} \)
-4 x (4z + 5) = z
(-4 x 4z) + (-4 x 5) = z
-16z - 20 = z
-16z - 20 - z = 0
-16z - z = 20
-17z = 20
z = \( \frac{20}{-17} \)
z = -1\(\frac{3}{17}\)

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.

7a x 7b = (7 x 7) (a x b) = 49ab

A quadrilateral is a shape with four sides. The perimeter of a quadrilateral is the sum of the lengths of its four sides.