AlgebraMediumx-intercept from a point and the y-intercept
Algebra practice question
In the xy-plane, line ℓ passes through the point (4, 1) and has y-intercept −7. What is the x-intercept of line ℓ?
Answer: 7/2 or 3.5
Slope = (1 − (−7))/(4 − 0) = 2, so y = 2x − 7. Set y = 0: x = 7/2.
Common wrong answers
- If you answered 2
- 2 is the slope.
- If you answered 7
- 7 is the magnitude of the y-intercept, not the x-intercept.
- If you answered -3.5
- −3.5 has the wrong sign.
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