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.

(3a)(6ab) - (4a²)(8b)
(3 x 6)(a x a x b) - (4 x 8)(a² x b)
(18)(a¹⁺¹ x b) - (32)(a²b)
18a²b - 32a²b
-14a²b

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 equal sign and the answer on the other.

7a - 4 = \( \frac{a}{-9} \)
-9 x (7a - 4) = a
(-9 x 7a) + (-9 x -4) = a
-63a + 36 = a
-63a + 36 - a = 0
-63a - a = -36
-64a = -36
a = \( \frac{-36}{-64} \)
a = \(\frac{9}{16}\)

The area of a parallelogram is equal to its length x width:

a = l x w
a = a x b
a = 6 x 5
a = 30

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 formula for circumference is circle diameter x π:

c = πd
c = 9π