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).

To multiply monomials, multiply the coefficients (the numbers that come before the variables) of each term, add the exponents of like variables, and multiply the different variables together.

2a x 8b = (2 x 8) (a x b) = 16ab

To factor a quadratic expression, apply the FOIL (First, Outside, Inside, Last) method in reverse.

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 -36 as well and sum (Inside, Outside) to equal 5. For this problem, those two numbers are -4 and 9. Then, plug these into a set of binomials using the square root of the First variable (y²):

y² + 5y - 36
y² + (-4 + 9)y + (-4 x 9)
(y - 4)(y + 9)

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, 1) and (2, 3) so the slope becomes: