# Functions Question?

An increasing function, f, is defined for x > n, where n is an integer. It is given that

f'(x) = x^2 − 6x + 8.

Find the least possible value of n.

the answer is 4 but i dont get it why its not 2 because least possible x value is 2.

### 1 Answer

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- King LeoLv 73 months agoFavourite answer
f’(x) = x² - 6x + 8

f(x) is increasing where f’(x) > 0

x² - 6x + 8 > 0

( x - 3 )² > 1

x < 2 and x > 4

but f is defined for x > n

∴ n = 4

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