AlgebraEasy–MediumZero of a linear function from its intercept and rate
Algebra practice question
For the linear function f, f(0) = 12, and f(x) decreases by 4 each time x increases by 1. For what value of x is f(x) = 0?
Answer: 3
f(x) = 12 − 4x, so f(x) = 0 when 4x = 12, x = 3.
Common wrong answers
- If you answered 4
- 4 is the rate of decrease, not the zero.
- If you answered 48
- 48 is 12 × 4, multiplying instead of dividing.
- If you answered -3
- −3 has the wrong sign.
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