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

z² - 2z - 8 = 0
(z + 2)(z - 4) = 0

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

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

So the solution is that z = -2 or 4

The surface area of a cylinder is 2πr² + 2πrh:

sa = 2πr² + 2πrh
sa = 2π(6²) + 2π(6 x 6)
sa = 2π(36) + 2π(36)
sa = (2 x 36)π + (2 x 36)π
sa = 72π + 72π
sa = 144π

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.

2y - 6 = \( \frac{y}{6} \)
6 x (2y - 6) = y
(6 x 2y) + (6 x -6) = y
12y - 36 = y
12y - 36 - y = 0
12y - y = 36
11y = 36
y = \( \frac{36}{11} \)
y = 3\(\frac{3}{11}\)

You can only add or subtract monomials that have the same variable and the same exponent. For example, 2a + 4a = 6a and 4a² - a² = 3a² but 2a + 4b and 7a - 3b cannot be combined. However, you can multiply and divide monomials with unlike terms. For example, 2a x 6b = 12ab.