Question

m.n giúp mk vs ạ
x²+5x+6=0

Answer 1

\(x^2+5x+6=0\)

\(\Leftrightarrow\left(x^2+2x\right)+\left(3x+6\right)=0\)

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

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

\(\Leftrightarrow\orbr{\begin{cases}x+2=0\\x+3=0\end{cases}\Leftrightarrow\orbr{\begin{cases}x=-2\\x=-3\end{cases}}}\)

Answer 2

x^2+2x+3x+6=0

x(x+2)+3(x+2)=0

(x+3)(x+2)=0

=> x= - 3 hoac -2

Answer 3

\(x^2+5x+6=0\)

<=> \(x^2+2x+3x+6=0\)

<=>\(\left(x^2+2x\right)+\left(3x+6\right)=0\)

<=> \(x\left(x+2\right)+3\left(x+2\right)=0\)

<=> \(\left(x+2\right)\left(x+3\right)=0\)

<=> x+2=0 hoặc x+3=0

<=> x= -2 hoặc x=-3

Vậy x=-2 ,x=-3

Answer 4

\(x^2+5x+6=0\)

=>\(x^2+2x+3x+6=0\)

=>\(x\left(x+2\right)+3\left(x+2\right)=0\)

=>\(\left(x+2\right)\left(x+3\right)=0\)

=>\(\orbr{\begin{cases}x+2=0\\x+3=0\end{cases}\Rightarrow\orbr{\begin{cases}x=-2\\x=-3\end{cases}}}\)