Slopeintercept form:  y = mx + b. 
Find m, the slope:  m = (1  5) / (3  1) = 2 
Substitute 2 (the slope) in for m:  y = 2x + b. 
To find b, substitute 1 for x and 5 for y:  5 = 2(1) + b. 
Solve for b: Click here to see how. 
b = 7. 
Final answer:  y = 2x + 7. 


