equation

The equation of the line that passes through the points (3,7) and (1,3) is

First, let's find the slope between the points

[ 7 -3] / [ 3 - 1]   =   4 / 2  =  2   = m

Now, using this and either point - I'll use the second - we can write the equation

y - y1   =  m (x - x1)     wher m= 2, and (x1, y1)  =  (1,3)

y - 3  = 2 (x - 1)   simplify

y - 3  =  2x  - 2     add 3 to both sides

y =  2x  + 1