Question

 Решите уравнение X^3-3X^2-8X+24=0 и из фото тоже!)

Answer 1

$x^3-3x^2-8x+24=0\ x^2(x-3)-8(x-3)=0\ (x-3)(x^2-8)=0\ x_1=3\ x_{2,3}=pm 2sqrt{2}$

Пример 7.
  $displaystyle frac{a^2-9b^2}{2a^2}cdot frac{a}{2a+6b}= frac{(a-3b)(a+3b)}{2a^2}cdot frac{a}{2(a+3b)} = frac{a-3b}{4a} \ \ \ if,,,a= sqrt{2} ;,,, b=sqrt{50} ,,,, then,,,,, frac{sqrt{2} -3sqrt{50} }{4sqrt{2} } = frac{sqrt{2} (1-3cdot 5)}{4sqrt{2} } =-3.5$

Пример 8.
$7+4(-5x-7) leq 4\ \ 7-20x-28 leq 4\ \ -20x leq 4+21\ \ -20x leq 25\ \ x geq -1.25$