AlgebraMediumIntercept from a slope and a point
Algebra practice question
A line in the xy-plane has a slope of −3/2 and passes through the point (4, 1). What is the y-intercept of the line?
Answer: 7
y = (−3/2)x + b. Substitute (4, 1): 1 = −6 + b, so b = 7.
Common wrong answers
- If you answered 1
- 1 is the y-coordinate of the given point, not the intercept.
- If you answered 5
- 5 comes from a slope of −1: 1 = −4 + b. The slope is −3/2, so (−3/2)(4) = −6.
- If you answered -5
- −5 comes from 1 + (−6), adding the product instead of subtracting it from 1.
More Algebra questions
- Medium
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Line k has equation y = (2/3)x + 1. Which equation represents a line perpendicular to line k?
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