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)(7ab) + (2a²)(5b)
(8 x 7)(a x a x b) + (2 x 5)(a² x b)
(56)(a¹⁺¹ x b) + (10)(a²b)
56a²b + 10a²b
66a²b

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.

6a + 5a = 11a

The area of a trapezoid is one-half the sum of the lengths of the parallel sides multiplied by the height:

a = ½(b + d)(h)
a = ½(8 + 9)(4)
a = ½(17)(4)
a = ½(68) = \( \frac{68}{2} \)
a = 34

The perimeter of a triangle is the sum of the lengths of its sides:

p = x + y + z
p = 8cm + 8cm + 7cm = 23cm

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.)

-4a(a - y)
-4(-1)(-1 + 6)
-4(-1)(5)
(4)(5)
20