Here is the data:
latitude (degrees N), x axis: 6, 18, 23, 30, 35, 42, 45, 52, 56, 56
april mean high temperature (degrees F), y axis: 89, 84, 97, 83, 63, 68, 45, 56, 47, 47

The equation I found was y=-1x+103.
WAIT, is it 0 for the latitude? Or temperature..?