Question

1. the temperature decreased from 15°c to -7°c. by how much did the temperature decrease?

Explanation:

Step1: Identify initial and final temps

Initial temp = $15^{\circ}C$, final temp = $- 7^{\circ}C$.

Step2: Calculate temperature decrease

We find the difference by subtracting final from initial: $15-(-7)$.
Since subtracting a negative is adding a positive, $15 - (-7)=15 + 7$.
$15+7 = 22$.

Answer:

$22^{\circ}C$