A rectangle is a parallelogram containing four right angles. Opposite sides (a = c, b = d) are equal and the perimeter is the sum of the lengths of all sides (a + b + c + d) or, comonly, 2 x length x width. The area of a rectangle is length x width. A square is a rectangle with four equal length sides. The perimeter of a square is 4 x length of one side (4s) and the area is the length of one side squared (s²).

An acute angle measures less than 90°, a right angle measures 90°, and an obtuse angle measures more than 90°.

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

z² - 4z - 32 = 0
(z + 4)(z - 8) = 0

For this expression to be true, the left side of the expression must equal zero. Therefore, either (z + 4) or (z - 8) must equal zero:

If (z + 4) = 0, z must equal -4
If (z - 8) = 0, z must equal 8

So the solution is that z = -4 or 8

A line on the coordinate grid can be defined by a slope-intercept equation: y = mx + b. For a given value of x, the value of y can be determined given the slope (m) and y-intercept (b) of the line. The slope of a line is change in y over change in x, \({\Delta y \over \Delta x}\), and the y-intercept is the y-coordinate where the line crosses the vertical y-axis.

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 40 as well and sum (Inside, Outside) to equal 13. For this problem, those two numbers are 5 and 8. Then, plug these into a set of binomials using the square root of the First variable (y²):

y² + 13y + 40
y² + (5 + 8)y + (5 x 8)
(y + 5)(y + 8)