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.

(9a)(2ab) - (9a²)(6b)
(9 x 2)(a x a x b) - (9 x 6)(a² x b)
(18)(a¹⁺¹ x b) - (54)(a²b)
18a²b - 54a²b
-36a²b

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.

3a⁶ - 4a⁶ = -1a⁶

The coordinate grid is composed of a horizontal x-axis and a vertical y-axis. The center of the grid, where the x-axis and y-axis meet, is called the origin.

To solve this equation, repeatedly do the same thing to both sides of the equation until the variable is isolated on one side of the > sign and the answer on the other.

-a + 7 > \( \frac{a}{3} \)
3 x (-a + 7) > a
(3 x -a) + (3 x 7) > a
-3a + 21 > a
-3a + 21 - a > 0
-3a - a > -21
-4a > -21
a > \( \frac{-21}{-4} \)
a > 5\(\frac{1}{4}\)