For this case, the first thing we must do is define variables.
We have then:
c: temperature in degrees celsius
f: temperature in Fahrenheit
The generic equation of the line is:

Where, the slope is given by:

Substituting values:

Rewriting:

We choose an ordered pair:

Substituting values in the generic equation:

Rewriting:
Answer: An equation of the line in slope-intercept form is:
See attached image.