a)сначала находим производную
<span>f(штрих)=(<span>4x-3x^2)штрих=4-6х</span></span>
<span><span>4-6х<span><0; 4<span><6х; 2/3<span><х ОТвет (2/3;+бесконечности)</span></span></span></span></span>
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<span><span><span><span><span>б)сначала опять находим производную</span></span></span></span></span>
<span><span><span><span><span><span>f(штрих)=(<span>x^2-5x)штрих=2х-5</span></span></span></span></span></span></span>
<span><span><span><span><span><span><span>2х-5<span><0; 2х<span><5; х<span><2,5 Ответ:(-бесконечности;2,5)</span></span></span></span></span></span></span></span></span></span>
Ответ:
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(x-5)(x+3)<=0
[-3;5]
3(x+3)<=4x+5
4x+5-3x-9>=0
x>=4
ответ [4;5]
x>=2
x<=4
возводим в квадрат
x-2+4-x+2sqrt((x-2)(4-x)<4
sqrt((x-2)(4-x)<1
-x^2+6x-8<1
x^2-6x+9>0
(x-3)^2>0
x<3 U x>3
ответ [2;3[ U ]3;4]