Advanced Math practice question

Answer: 4

For 0 ≤ x ≤ 4, |x| + |x − 4| = x + (4 − x) = 4; outside that interval the sum is larger. The minimum is 4.

Common wrong answers

If you answered 0

0 would need both absolute values to be 0 at once, which is impossible.

If you answered 2

2 is the midpoint of 0 and 4, where f(2) = 4, not 2.

If you answered 8

8 is f(6) or f(−2), values outside the flat interval, not the minimum.

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