First let us find the slope;
Slope for (x₁, y₁) and (x₂, y₂): (1, 3) and (3, 7)
Slope: (y₂ -y₁) / (x₂ -x₁)
Slope: ( 7 - 3) / (3 - 1) = 4/2
Slope = 2
Using (y - y₁) = m(x - x₁)
using (1, 3) as (x₁, y₁)
(y - y₁) = m(x - x₁)
(y - 3) = 2(x - 1)
y - 3 = 2x -2
y = 2x - 2 + 3
y = 2x + 1
y = 2x + 1 is the equation of line through both points in slope intercept form.
