To multiply terms with exponents, the base of both exponents must be the same. In this case they are so multiply the coefficients and add the exponents:

-9y³ x 3y⁵
(-9 x 3)y^{(3 + 5)}
-27y⁸

Average speed in miles per hour is the number of miles traveled divided by the number of hours:

Solving for time:

time = \( \frac{\text{distance}}{\text{speed}} \)
time = \( \frac{270mi}{45mph} \)
6 hours

A rational number (or fraction) is represented as a ratio between two integers, a and b, and has the form \({a \over b}\) where a is the numerator and b is the denominator. An improper fraction (\({5 \over 3} \)) has a numerator with a greater absolute value than the denominator and can be converted into a mixed number (\(1 {2 \over 3} \)) which has a whole number part and a fractional part.

Monica scored 78% on the test meaning she earned 78% of the possible points on the test. There were 200 possible points on the test so she earned 200 x 0.78 = 156 points. Each question is worth 2 points so she got \( \frac{156}{2} \) = 78 questions right.

The commutative property states that, when adding or multiplying numbers, the order in which they're added or multiplied does not matter. For example, 3 + 4 and 4 + 3 give the same result, as do 3 x 4 and 4 x 3.