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.

A quadrilateral is a shape with four sides. The perimeter of a quadrilateral is the sum of the lengths of its four sides.

Angles around a line add up to 180°. Angles around a point add up to 360°. When two lines intersect, adjacent angles are supplementary (they add up to 180°) and angles across from either other are vertical (they're equal).

The surface area of a cube is (2 x length x width) + (2 x width x height) + (2 x length x height):

sa = 2lw + 2wh + 2lh
sa = (2 x 6 x 2) + (2 x 2 x 6) + (2 x 6 x 6)
sa = (24) + (24) + (72)
sa = 120

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.

-8z - 3 > \( \frac{z}{-5} \)
-5 x (-8z - 3) > z
(-5 x -8z) + (-5 x -3) > z
40z + 15 > z
40z + 15 - z > 0
40z - z > -15
39z > -15
z > \( \frac{-15}{39} \)
z > -\(\frac{5}{13}\)