AlgebraEasy–MediumIntercept of a line through a given point
Algebra practice question
In the xy-plane, the line y = 2x + b passes through the point (3, 1). What is the value of b?
Answer: -5 or −5
Substitute x = 3, y = 1: 1 = 2(3) + b, so b = 1 − 6 = −5.
Common wrong answers
- If you answered 5
- 5 has the wrong sign: b = 1 − 6.
- If you answered 7
- 7 is 1 + 6, adding instead of subtracting.
- If you answered -1
- −1 comes from 1 = 2 + b, forgetting to multiply the slope by 3.
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