(t+3)(t-8)-t²= t²-8t+3t-24-t²= -5t-24
-5*(-15)-24= 75-24= 51
D=25-4*2*(-6)=25+48=73
x1=-5+√73/-4
x2=-5-√73/-4
<span>x³+2x²-x-2=0</span>
<span>открываем скобки</span>
<span>x²(x+2)-(x+2)=0</span>
<span>получаем</span>
<span>(x²-1)(x+2)=0</span>
<span>отсюда</span>
<span>(x-1)(x+1)(x+2)=0</span>
<span>x1 = 1</span>
<span>x2 = -1</span>
<span>x3 = -2</span>