Question

Không làm tắt nha mn

Answer 1

a) Ta có: \(x^2-2x=0\)

\(\Leftrightarrow x\left(x-2\right)=0\)

\(\Leftrightarrow\left[{}\begin{matrix}x=0\\x=2\end{matrix}\right.\)

b) Ta có: \(\left(x+1\right)^2-\left(2x+3\right)^2=0\)

\(\Leftrightarrow\left(x+1-2x-3\right)\left(x+1+2x+3\right)=0\)

\(\Leftrightarrow\left(-x-2\right)\left(3x+4\right)=0\)

\(\Leftrightarrow\left[{}\begin{matrix}-x-2=0\\3x+4=0\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}-x=2\\3x=-4\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=-2\\x=\dfrac{-4}{3}\end{matrix}\right.\)

c) Ta có: \(27x^3-27x+9x-1=0\)

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

\(\Leftrightarrow3x-1=0\)

hay \(x=\dfrac{1}{3}\)