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

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.

8z - 9 = \( \frac{z}{9} \)
9 x (8z - 9) = z
(9 x 8z) + (9 x -9) = z
72z - 81 = z
72z - 81 - z = 0
72z - z = 81
71z = 81
z = \( \frac{81}{71} \)
z = 1\(\frac{10}{71}\)

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.

-7c + 1 = 9 - 9c
-7c = 9 - 9c - 1
-7c + 9c = 9 - 1
2c = 8
c = \( \frac{8}{2} \)
c = 4

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:

(y + 9)(y - 2)
(y x y) + (y x -2) + (9 x y) + (9 x -2)
y² - 2y + 9y - 18
y² + 7y - 18

A triangle is a three-sided polygon. It has three interior angles that add up to 180° (a + b + c = 180°). An exterior angle of a triangle is equal to the sum of the two interior angles that are opposite (d = b + c). The perimeter of a triangle is equal to the sum of the lengths of its three sides, the height of a triangle is equal to the length from the base to the opposite vertex (angle) and the area equals one-half triangle base x height: a = ½ base x height.