Given points are

Next, find the slope.

Substitute 29 for y₂,  20 for y₁, 12 for x₂, and 15 for x₁  in slope formula.

\ \

                         (Subtract: )

                              (Subtract: )

                          (Simplify) \ \

                                          (Cancel common terms)

You know the slope and a point on the line, so use point - slope form

with either given point to write an equation of line.

Choose

              (Substitute 20 for y₁, 15 for x₁ and ) \ \

     (Apply distributive property: )

              (Multiply: )

                   (Divide: )

   (Add 20 to each side)

             (Apply additive inverse property: )

                  (Apply additive identity property: )

                                (Add: )

The equation of line is .