The first step to solve a quadratic expression that's not set to zero is to solve the equation so that it is set to zero:

z² - 7z - 59 = -5z + 4
z² - 7z - 59 - 4 = -5z
z² - 7z + 5z - 63 = 0
z² - 2z - 63 = 0

Next, factor the quadratic equation:

z² - 2z - 63 = 0
(z + 7)(z - 9) = 0

For this expression to be true, the left side of the expression must equal zero. Therefore, either (z + 7) or (z - 9) must equal zero:

If (z + 7) = 0, z must equal -7
If (z - 9) = 0, z must equal 9

So the solution is that z = -7 or 9

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

sa = 2πr² + 2πrh
sa = 2π(8²) + 2π(8 x 5)
sa = 2π(64) + 2π(40)
sa = (2 x 64)π + (2 x 40)π
sa = 128π + 80π
sa = 208π

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

c² + 6c + 8 = 0
(c + 2)(c + 4) = 0

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

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

So the solution is that c = -2 or -4

When solving an equation with two variables, 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.)

To combine like terms, add or subtract the coefficients (the numbers that come before the variables) of terms that have the same variable raised to the same exponent.

9a + 6a = 15a