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.

8a + 2a = 10a

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.

8a⁹ + 5a⁹ = 13a⁹

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.

(8a)(3ab) + (9a²)(2b)
(8 x 3)(a x a x b) + (9 x 2)(a² x b)
(24)(a¹⁺¹ x b) + (18)(a²b)
24a²b + 18a²b
42a²b

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 - 5)(y - 3)
(y x y) + (y x -3) + (-5 x y) + (-5 x -3)
y² - 3y - 5y + 15
y² - 8y + 15

The volume of a cube is height x length x width:

v = h x l x w
v = 7 x 5 x 7
v = 245