The problem
A line passes through (2, 1) and (8, −2). Find its slope m and y-intercept b.
Answer
m = −1/2, b = 2
Worked solution
- Slope = (−2 − 1) / (8 − 2) = −3 / 6 = −1/2.
- Put one point into y = mx + b: 1 = −1/2 · 2 + b.
- 1 = −1 + b, so b = 2. The line is y = −1/2x + 2.
How members answered
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