Giải phương trình a. (x-1)(x^2+5x-2), b. x^2+(x+2)(11x-7)=4

* Hướng dẫn giải

$\begin{array}{l}\left(x-1\right)\left(x^2+5x-2\right)-\left(x^3-1\right)=0\\ \iff \left(x-1\right)\left(x^2+5x-2\right)-\left(x-1\right)\left(x^2+x+1\right)=0\\ \iff \left(x-1\right)\left(4x-3\right)=0\iff \left[\begin{array}{l}x=1\\ x=\frac{3}{4}\end{array}\right.\end{array}$