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 = 9a

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)(6ab) - (6a²)(9b)
(2 x 6)(a x a x b) - (6 x 9)(a² x b)
(12)(a¹⁺¹ x b) - (54)(a²b)
12a²b - 54a²b
-42a²b

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.)

2c(c - y)
2(3)(3 + 4)
2(3)(7)
(6)(7)
42

A trapezoid is a quadrilateral with one set of parallel sides.

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