You can only add or subtract monomials that have the same variable and the same exponent. For example, 2a + 4a = 6a and 4a² - a² = 3a² but 2a + 4b and 7a - 3b cannot be combined. However, you can multiply and divide monomials with unlike terms. For example, 2a x 6b = 12ab.

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

v = h x l x w
v = 9 x 3 x 6
v = 162

The first step to solve a quadratic expression that's not set to zero is to solve the equation so that it is set to zero:

a² - 5a - 27 = -5a - 2
a² - 5a - 27 + 2 = -5a
a² - 5a + 5a - 25 = 0
a² - 25 = 0

Next, factor the quadratic equation:

a² - 25 = 0
(a - 5)(a + 5) = 0

For this expression to be true, the left side of the expression must equal zero. Therefore, either (a - 5) or (a + 5) must equal zero:

If (a - 5) = 0, a must equal 5
If (a + 5) = 0, a must equal -5

So the solution is that a = 5 or -5

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.

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.

(5a)(6ab) - (3a²)(2b)
(5 x 6)(a x a x b) - (3 x 2)(a² x b)
(30)(a¹⁺¹ x b) - (6)(a²b)
30a²b - 6a²b
24a²b