## Objective:

**To use two points to write the equation of a line.**

## Notes:

### Slope Formula:

### Steps to finding the equation:

- Write "
*y = mx + b*". - Find the slope. (For help see section 4.4).
- Replace the variable
*m*with the slope you found in step 2. - Choose one of your points. Make note of its coordinates.
- Replace the variable
*x*with the x-coordinate of the point from step 4 and*y*with the y-coordinate of the point. - Solve for the only variable you have left,
*b*. - Write "
*y = mx + b*" again. - Replace
*m*with the slope and*b*with the value you found in step 6.

## Examples:

### Solve:

- Write the equation of the line containing the points (−1, 1) and (0, 3).

- Write the equation of the line containing the points (4, 4) and (−2, −1).

- Write the equation of the line containing the points (3, −4) and (3, 8).