тут на самом деле все просто. смотри фото
<span><span>3<span>x2</span> - 124x - 84 = 0</span>
<span><span>D = (-124)2 - 4·3·(-84)</span> = 16384</span>
<span><span><span>x1 = </span><span>124 - √16384</span> = <span><span>-2</span>3</span></span>2·3</span>
<span><span><span>x2 = </span><span>124 + √16384</span> = 42</span><span>2·3
</span></span></span>
F'(x)=6x^2+5x-1 формула (x^n)'=nx^(n-1)
f'(x)>0
6x^2+5x-1>0 6x^2+5x-1=0 a+c=b⇒x1=-1 x2=-c/a=1/6
(x+1)(x-1/6)>0
+ -1 - 1/6 +
ответ (-00,-1)∪(1/6,+00)