Posted by joshua on .
Write the slopeintercept equation for the line through (3, 7) and (9, 3)

Algebra 
drwls,
The slopeintercept form is y = mx + b
7 = m*3 + b
3 = m*9 + b
Subtract second equation from the first, to eliminate the unknown b.
4 = 6m
m = 2/3
7 = 2 + b
b = 9
y = (2/3)x + 9