Answer
(a) The graph is on the figure below.
(b)
1) the slope represents how many degrees Fahrenheit correspond to the change of temperature of one degree Celsius.
2) the intercept with $C$ axis says what is the temperature in Celsius when the temperature in Fahrenheit is $0$
3) the intercept with $F$ axis says what is the temperature in Fahrenheit when the temperature in Celsius is $0$.
Work Step by Step
To sketch the graph first find the intercepts with the axes and then draw the line through the intercepts:
1) With $C$ axis for $F=0$ we have
$$0=\frac{9}{5}C+32\Rightarrow \frac{9}{5}C=-32\Rightarrow C=\frac{160}{9}=17.78.$$
2) With $F$ axis for $C=0$ we have
$$F=\frac{9}{5}\cdot0+32=32.$$
The graph is shown in the figure below.
