AlgebraVery hardSlope constant from equal outputs
Algebra practice question
The linear functions f and g are defined by f(x) = 2x + 5 and g(x) = kx − 1, where k is a constant. If f(3) = g(3), what is the value of k?
Answer: 4
f(3) = 11, so 3k − 1 = 11 and k = 4.
Common wrong answers
- If you answered 2
- 2 assumes the slopes must match, but the functions are equal only at x = 3.
- If you answered 12
- 12 is 3k, not k.
- If you answered 3.33
- 3.33 divides 10 by 3, forgetting the −1.
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