Worked examples
Two examples
Example 1
Write the equation of the line through (1, 3) and (3, 7).
- Slope: (7 − 3) ÷ (3 − 1) = 2.
- Find b with one point: 3 = 2 × 1 + b, so b = 1.
Answer: y = 2x + 1
Example 2
Write the equation of the line through (0, 5) and (2, −1).
- Slope: (−1 − 5) ÷ (2 − 0) = −3.
- The point (0, 5) is the y-intercept, so b = 5.
Answer: y = −3x + 5
Where this is taught: Lines on the Grid, “Slope from two points”
The drill
Ten problems
This drill also has challenge problems. They use the same skill, set up the way the GED test sometimes sets up a problem, so that it looks new at first.
How many:
Type the right-hand side, like 2x - 5 (fractions like 3/4x are fine). Then press Check my answers at the bottom.Write each answer on the line. The answer key, with the reasoning, is on the last page.