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

b² - 2b - 8 = 0
(b + 2)(b - 4) = 0

For this expression to be true, the left side of the expression must equal zero. Therefore, either (b + 2) or (b - 4) must equal zero:

If (b + 2) = 0, b must equal -2
If (b - 4) = 0, b must equal 4

So the solution is that b = -2 or 4

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 solve this equation, replace the variables with the values given and then solve the now variable-free equation. (Remember order of operations, PEMDAS, Parentheses, Exponents, Multiplication/Division, Addition/Subtraction.)

-6b(b - y)
-6(9)(9 + 4)
-6(9)(13)
(-54)(13)
-702

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 > sign and the answer on the other.

-5y + 9 > -4 + 9y
-5y > -4 + 9y - 9
-5y - 9y > -4 - 9
-14y > -13
y > \( \frac{-13}{-14} \)
y > \(\frac{13}{14}\)

Perimeter is equal to the sum of the four sides:

p = a + b + c + d
p = 9 + 6 + 7 + 3
p = 25