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 line on the coordinate grid can be defined by a slope-intercept equation: y = mx + b. For a given value of x, the value of y can be determined given the slope (m) and y-intercept (b) of the line. The slope of a line is change in y over change in x, \({\Delta y \over \Delta x}\), and the y-intercept is the y-coordinate where the line crosses the vertical y-axis.

The first step to solve a quadratic equation that's set to zero is to factor the quadratic equation:

z² + 2z - 8 = 0
(z - 2)(z + 4) = 0

For this expression to be true, the left side of the expression must equal zero. Therefore, either (z - 2) or (z + 4) must equal zero:

If (z - 2) = 0, z must equal 2
If (z + 4) = 0, z must equal -4

So the solution is that z = 2 or -4

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 3 x 6) + (2 x 6 x 2) + (2 x 3 x 2)
sa = (36) + (24) + (12)
sa = 72

A line segment is a portion of a line with a measurable length. The midpoint of a line segment is the point exactly halfway between the endpoints. The midpoint bisects (cuts in half) the line segment.