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

To solve this equation, repeatedly do the same thing to both sides of the equation until the variable is isolated on one side of the equal sign and the answer on the other.

-5b + 4 = \( \frac{b}{4} \)
4 x (-5b + 4) = b
(4 x -5b) + (4 x 4) = b
-20b + 16 = b
-20b + 16 - b = 0
-20b - b = -16
-21b = -16
b = \( \frac{-16}{-21} \)
b = \(\frac{16}{21}\)

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)(7ab) - (5a²)(5b)
(2 x 7)(a x a x b) - (5 x 5)(a² x b)
(14)(a¹⁺¹ x b) - (25)(a²b)
14a²b - 25a²b
-11a²b

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.)

3c(c - z)
3(-3)(-3 + 2)
3(-3)(-1)
(-9)(-1)
9

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