16Hit1600
AlgebraVery hardInput where a decreasing linear function turns negative

Algebra practice question

For the linear function f, f(3) = 5 and f(8) = −5. For what value of x is f(x) = 0?

Answer: 5.5 or 11/2

The slope is −10/5 = −2, so f(x) = 11 − 2x, which is 0 at x = 5.5.

Common wrong answers

If you answered 5
5 averages 3 and 8 incorrectly for this function; check 11 − 10 = 1.
If you answered 11
11 is f(0).
If you answered -2
−2 is the slope.

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