Question

(x+1)(x+2)=(2-x)(x+2)

Answer 1

(x+1)(x+2)=(2-x)(x+2)

<=>(x+1)(x+2)-(2-x)(x+2)=0

<=> (x+1-2+x)(x+2)=0

<=> (2x - 1 )(x+2)=0

<=>\(\left[{}\begin{matrix}2x-1=0\\x+2=0\end{matrix}\right.\)

<=> \(\left[{}\begin{matrix}x=\frac{1}{2}\\x=-2\end{matrix}\right.\)

Vậy S = \(\left\{\frac{1}{2};-2\right\}\)

Answer 2

(x+1)(x+2) = (2-x)(x+2)

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

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

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

\(\Leftrightarrow\left[{}\begin{matrix}x+2=0\\2x-1=0\end{matrix}\right.\)

\(\Leftrightarrow\left[{}\begin{matrix}x=-2\\x=\frac{1}{2}\end{matrix}\right.\)

Vậy pt có tập nghiệm S = \(\left\{-2;\frac{1}{2}\right\}\)

Answer 3