## Thinking Mathematically (6th Edition)

(a) $m = \frac{9}{5}$ The slope shows that the change in Fahrenheit temperature is $\frac{9}{5}$ degrees for each degree change in Celsius temperature. (b) $F = \frac{9}{5}C+32$
To find the slope if the line $m$, we can use the point (0,32) and the point (20,68). $m = \frac{\Delta F}{\Delta C}$ $m = \frac{68-32}{20-0}$ $m = \frac{36}{20}$ $m = \frac{9}{5}$ The slope shows that the change in Fahrenheit temperature is $\frac{9}{5}$ degrees for each degree change in Celsius temperature. (b) When C = 0 then F = 32, so the y-intercept is 32. Note that F is on the y-axis and C is on the x-axis. $y = mx + b$ $F = \frac{9}{5}C+32$