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 + 7)
(y x y) + (y x 7) + (1 x y) + (1 x 7)
y² + 7y + y + 7
y² + 8y + 7

A monomial contains one term, a binomial contains two terms, and a polynomial contains more than two terms.

A parallelogram is a quadrilateral with two sets of parallel sides. Opposite sides (a = c, b = d) and angles (red = red, blue = blue) are equal. The area of a parallelogram is base x height and the perimeter is the sum of the lengths of all sides (a + b + c + d).

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.

(7a)(3ab) + (3a²)(4b)
(7 x 3)(a x a x b) + (3 x 4)(a² x b)
(21)(a¹⁺¹ x b) + (12)(a²b)
21a²b + 12a²b
33a²b

A right angle measures 90 degrees and is the intersection of two perpendicular lines. In diagrams, a right angle is indicated by a small box completing a square with the perpendicular lines.