Question

ДАЮ 40 БАЛЛОВ!
Решить неравенство f'(x)$\leq$0, если f(x)=4x+2$x^{2}$

Answer 1

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Answer 2

$\displaystyle\bf\\f(x)=4x+2x^{2} \\\\f'(x)=4\cdot(x)'+2\cdot(x^{2} )'=4\cdot 1+2\cdot 2x=4+4x\\\\f'(x)\leq 0\\\\4+4x\leq 0\\\\41\Big]x\leq -4\\\\x\leq -1\\\\Otvet: \ \Big(-\infty \ ; \ -1\Big]$