The coordinate grid is composed of a horizontal x-axis and a vertical y-axis. The center of the grid, where the x-axis and y-axis meet, is called the origin.

A triangle is a three-sided polygon. It has three interior angles that add up to 180° (a + b + c = 180°). An exterior angle of a triangle is equal to the sum of the two interior angles that are opposite (d = b + c). The perimeter of a triangle is equal to the sum of the lengths of its three sides, the height of a triangle is equal to the length from the base to the opposite vertex (angle) and the area equals one-half triangle base x height: a = ½ base x height.

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.

(9a)(7ab) + (6a²)(3b)
(9 x 7)(a x a x b) + (6 x 3)(a² x b)
(63)(a¹⁺¹ x b) + (18)(a²b)
63a²b + 18a²b
81a²b

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).

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:

y² + 3y - 70 = 4y + 2
y² + 3y - 70 - 2 = 4y
y² + 3y - 4y - 72 = 0
y² - y - 72 = 0

Next, factor the quadratic equation:

y² - y - 72 = 0
(y + 8)(y - 9) = 0

For this expression to be true, the left side of the expression must equal zero. Therefore, either (y + 8) or (y - 9) must equal zero:

If (y + 8) = 0, y must equal -8
If (y - 9) = 0, y must equal 9

So the solution is that y = -8 or 9