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.

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 -8 as well and sum (Inside, Outside) to equal 2. For this problem, those two numbers are -2 and 4. Then, plug these into a set of binomials using the square root of the First variable (y²):

y² + 2y - 8
y² + (-2 + 4)y + (-2 x 4)
(y - 2)(y + 4)

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.

7a - 2a = 5a

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)(6ab) - (3a²)(6b)
(9 x 6)(a x a x b) - (3 x 6)(a² x b)
(54)(a¹⁺¹ x b) - (18)(a²b)
54a²b - 18a²b
36a²b

The Pythagorean theorem defines the relationship between the side lengths of a right triangle. The length of the hypotenuse squared (c²) is equal to the sum of the two perpendicular sides squared (a² + b²): c² = a² + b² or, solved for c, \(c = \sqrt{a + b}\)