The original price of a vest for sale at a department store is $80. The store is having a 20%-off sale, and you have a coupon th
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Answer:
-1/2
Step-by-step explanation:
In a linear relationship, the rate of change of one variable with respect to the other is <em>constant</em>. When we talk about <em>change</em>, we're looking for a <em>difference</em> of values.
If we look at the first and second rows, the change in x is 1 - (-1) = 2, while the change in y is 9 - 10 = -1. Usually we refer to these changes as Δx and Δy (read like "delta-x" and "delta-y"), and the <em>rate of change </em>is the number we get by dividing one of these by the other.
The rate of change we're used to seeing, sometimes called the <em>slope</em>, is Δy/Δx. So, using the values we've already found: