Algebra practice question

Answer: 8

The slope is (21 − 9)/(5 − 2) = 4, so f rises by 4 for each unit of x. From x = 6 to x = 8 is 2 units: 4 × 2 = 8.

Common wrong answers

If you answered 2

2 is the width of the interval, not the change in f.

If you answered 4

4 is the change per ONE unit of x; the interval is 2 units.

If you answered 12

12 is the change from x = 2 to x = 5, not from 6 to 8.

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