Question

x(x-4+1)=3x-5 tìm x biết

Answer 1

\(x\left(x-4+1\right)=3x-5\\ \Rightarrow x\left(x-3\right)=3x-5\\ \Rightarrow x^2-3x-3x+5=0\\ \Rightarrow x^2-6x+5=0\\ \Rightarrow\left(x^2-x\right)-\left(5x-5\right)=0\\ \Rightarrow x\left(x-1\right)-5\left(x-1\right)=0\\ \Rightarrow\left(x-1\right)\left(x-5\right)=0\\ \Rightarrow\left[{}\begin{matrix}x-1=0\\x-5=0\end{matrix}\right.\\ \Rightarrow\left[{}\begin{matrix}x=1\\x=5\end{matrix}\right.\)