The area of a triangle is equal to ½ base x height:

a = ½bh
a = ½ x 8 x 5 = \( \frac{40}{2} \) = 20

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)(9ab) + (7a²)(4b)
(7 x 9)(a x a x b) + (7 x 4)(a² x b)
(63)(a¹⁺¹ x b) + (28)(a²b)
63a²b + 28a²b
91a²b

To factor a quadratic expression, apply the FOIL method (First, Outside, Inside, Last) in reverse. First, find the two Last terms that will multiply to produce -12 as well and sum (Inside, Outside) to equal -1. For this problem, those two numbers are -4 and 3. Then, plug these into a set of binomials using the square root of the First variable (y²):

y² - y - 12
y² + (-4 + 3)y + (-4 x 3)
(y - 4)(y + 3)

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

v = h x l x w
v = 4 x 7 x 1
v = 28

An equation is two expressions separated by an equal sign. The key to solving equations is to repeatedly do the same thing to both sides of the equation until the variable is isolated on one side of the equal sign and the answer on the other.