To solve this equation, 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.)

-9a(a - z)
-9(3)(3 + 5)
-9(3)(8)
(-27)(8)
-216

To multiply binomials, use the FOIL method. FOIL stands for First, Outside, Inside, Last and refers to the position of each term in the parentheses:

(y - 3)(y - 1)
(y x y) + (y x -1) + (-3 x y) + (-3 x -1)
y² - y - 3y + 3
y² - 4y + 3

To solve this equation, isolate the variable for which you are solving (a) on one side of the equation and put everything else on the other side.

-9a + 2y = 5a + 8y - 9
-9a = 5a + 8y - 9 - 2y
-9a - 5a = 8y - 9 - 2y
-14a = 6y - 9
a = \( \frac{6y - 9}{-14} \)
a = \( \frac{6y}{-14} \) + \( \frac{-9}{-14} \)
a = -\(\frac{3}{7}\)y + \(\frac{9}{14}\)

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, \(c = \sqrt{a + b}\)

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.