The slope-intercept equation for a line is y = mx + b where m is the slope and b is the y-intercept of the line. From the graph, you can see that the y-intercept (the y-value from the point where the line crosses the y-axis) is -1. 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, 0) so the slope becomes:

Plugging these values into the slope-intercept equation:

y = \(\frac{1}{2}\)x - 1

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.

Parallel lines are lines that share the same slope (steepness) and therefore never intersect. A transversal occurs when a set of parallel lines are crossed by another line. All of the angles formed by a transversal are called interior angles and angles in the same position on different parallel lines equal each other (a° = w°, b° = x°, c° = z°, d° = y°) and are called corresponding angles. Alternate interior angles are equal (a° = z°, b° = y°, c° = w°, d° = x°) and all acute angles (a° = c° = w° = z°) and all obtuse angles (b° = d° = x° = y°) equal each other. Same-side interior angles are supplementary and add up to 180° (e.g. a° + d° = 180°, d° + c° = 180°).

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 - 1)(y + 9)
(y x y) + (y x 9) + (-1 x y) + (-1 x 9)
y² + 9y - y - 9
y² + 8y - 9

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

z² - 3z - 28 = 0
(z + 4)(z - 7) = 0

For this expression to be true, the left side of the expression must equal zero. Therefore, either (z + 4) or (z - 7) must equal zero:

If (z + 4) = 0, z must equal -4
If (z - 7) = 0, z must equal 7

So the solution is that z = -4 or 7