How do you find the maximum value of $-3(sqrt(x-9) + 12)$ ?

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Answer 1 · 2018-01-13T19:41:04

maximum value: $-36$

You were probably intended to use derivatives, but here is a solution from a different approach.

Note that $sqrt(x-9) >= 0$

$hArr (sqrt(x-9)+12) >= 12$

$hArr -3(sqrt(x-9)+12) <= -36$

How do you find the maximum value of -3(sqrt(x-9) + 12)-3(sqrt(x-9) + 12)?