To factor a quadratic expression, apply the FOIL method (First, Outside, Inside, Last) in reverse. First, find the two Last terms that will multiply to produce -2 as well and sum (Inside, Outside) to equal -1. For this problem, those two numbers are -2 and 1. Then, plug these into a set of binomials using the square root of the First variable (y²):

y² - y - 2
y² + (-2 + 1)y + (-2 x 1)
(y - 2)(y + 1)

The entire length of this line is represented by AD which is AB + BD:

AD = AB + BD

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 + 7)(y - 2)
(y x y) + (y x -2) + (7 x y) + (7 x -2)
y² - 2y + 7y - 14
y² + 5y - 14

The slope of this line is the change in y divided by the change in x. The endpoints of this line segment are at (-2, -2) and (2, -4) so the slope becomes:

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.