Question

tìm x biết: 4x(x+3)=x+3

Answer 1

ta có 4x(x+3)=x+3

<=>4x(x+3)-(x+3)=0

<=>(x+3)(4x-1)=0

=> x+3 =0 hoặc 4x-1 =0

=>x=-3 hoặc x= 1/4

vậy x thuộc  {-3; 1/4}

Answer 2

\(4x\left(x+3\right)=\left(x+3\right)\)

\(\Leftrightarrow4x\left(x+3\right)-\left(x+3\right)=0\)

\(\Leftrightarrow\left(x+3\right)\left(4x-1\right)=0\)

\(\Leftrightarrow\orbr{\begin{cases}x+3=0\\4x-1=0\end{cases}\Leftrightarrow\orbr{\begin{cases}x=-3\\x=\frac{1}{4}\end{cases}}}\)

Answer 3

\(\Leftrightarrow4x\left(x+3\right)-\left(x+3\right)=0\Leftrightarrow\left(x+3\right)\left(4x-1\right)=0\\ \)

\(\orbr{\begin{cases}x+3=0\\4x-1=0\end{cases}\Leftrightarrow\orbr{\begin{cases}x=-3\\x=\frac{1}{4}\end{cases}}}\)