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.

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

For parallel lines with a transversal, the following relationships apply:

• angles in the same position on different parallel lines equal each other (a° = w°, b° = x°, c° = z°, d° = y°)
• alternate interior angles are equal (a° = z°, b° = y°, c° = w°, d° = x°)
• all acute angles (a° = c° = w° = z°) and all obtuse angles (b° = d° = x° = y°) equal each other
• same-side interior angles are supplementary and add up to 180° (e.g. a° + d° = 180°, d° + c° = 180°)

Applying these relationships starting with d° = 156, the value of y° is 156.

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.

(3a)(5ab) + (5a²)(8b)
(3 x 5)(a x a x b) + (5 x 8)(a² x b)
(15)(a¹⁺¹ x b) + (40)(a²b)
15a²b + 40a²b
55a²b

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 + 1)(y + 4)
(y x y) + (y x 4) + (1 x y) + (1 x 4)
y² + 4y + y + 4
y² + 5y + 4