How do you multiply 20 times 9 times 5

What you would have to do first is do one step at a time. So first you would have to do 20x9 first and you know which property you could use. The associative property of multiplication because you can use parenthesis to figure out much easier. So you could either do (20x9)x5 or (9x5)x20 because it wouldn't matter and it would get you to the same answer because we were just using the commutative property of multiplication and so if you were to calculate this you would get 900 as your final answer.

In this problem it decreased 20%

the formula of a slope:

we have the points (-2, 7) and (2, 3). substitute:

answer: the slope is equal -1.