Question

5х в кубе - 15х в квадрате - х + 3= 0

Answer 1

$5x^3-15x^2-x+3=0\ 5x^2*(x-3)-(x-3)=0\ (x-3)*(5x^2-1)=0\ x-3=0; 5x^2-1=0\ x=3; x^2=frac{1}{5}\ x=3; x=frac{sqrt{5}}{5}; x=-frac{sqrt{5}}{5}$

Ответ: $x=3; frac{sqrt{5}}{5}}; -frac{sqrt{5}}{5}}$