Tìm x, biết:

$$\begin{gathered} a\left)x\right(x-2)+x-2=0; \\ b)5x(x-3)-x+3=0; \end{gathered}$$

Giải:

$$\begin{gathered} a) x(x - 2) + x - 2 = 0 \\ (x - 2\left)\right(x + 1) = 0 \\ Hoặc x - 2 = 0 \Rightarrow x = 2 \\ Hoặc x + 1 = 0 \Rightarrow x =-1 \\ Vậy x = -1; x = 2 \end{gathered}$$

$$\begin{gathered} b. 5x(x - 3) - x + 3 = 0 \\ 5x(x - 3) - (x - 3) = 0 \\ (x - 3)(5x - 1) = 0 \\ Hoặc x - 3 = 0 \Rightarrow x = 3 \\ Hoặc 5x - 1 = 0 \Rightarrow x = \frac{1}{5} \\ Vậy x = \frac{1}{5}; x = 3. \end{gathered}$$