1. How to Write an Equation of a Line Given TWO points
Write down y = mx + b.
Use the slope formula to find m.
Pick one of the ordered pairs & substitute slope for m and the point (x, y).
Solve for b.
Substitute m and b into the equation.

2. Equation of a Line - Given 2 points
Example 1: (2, 3) (4, 5)
y = mx + b
3 = 1(2) + b
b = 1
y = x + 1

3. Equation of a Line - Given 2 points
Example 2: (2, 3) (-4, 15)
y = -2x + 7

4. Equation of a Line - Given 2 points
Example 3: (2, 2) (0, 4)
y = -x + 4

5. Equation of a Line - Given 2 points
Example 4:
(2,3) (1,4)
y = -x + 5

6. Equation of a Line - Given 2 points
Example 5:
(4,5) (5,2)
y = -3x + 17

7. Equation of a Line - Given 2 points
  Example 6:
(6, – 8) (2, – 8)
y = -8