Example 15. Use your calculator to find the equation of the line through the points (2, 7) and (5, 13).
Answer: 
Example 16. Use your calculator to find the equation of the line that passes through (-2, -3) and (-4, -5).
Answer: 
Example 17. Find the equation of the line with slope 2.5 and having a y-intercept of (0, 4).
Answer: 