Tìm x, biết: 3x(x – 1) + x – 1 = 0

Đề bài: Tìm x, biết: 3x(x – 1) + x – 1 = 0.

Trả lời

Hướng dẫn giải:

Ta có: 3x(x – 1) + x – 1 = 0

$\iff$3x(x – 1) + (x – 1) = 0

$\iff$(x – 1)(3x + 1) = 0

$$\begin{gathered} \iff \left[\begin{array}{l}x-1=0\\ 3x+1=0\end{array}\right. \\ \iff \left[\begin{array}{l}x=1\\ x=\frac{-1}{3}\end{array}\right. \end{gathered}$$