Question

giúp mk vs ạ
 x² + 5x +6 = 0

Answer 1

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

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

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

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

\(\Rightarrow\left[\begin{array}{nghiempt}x+2=0\\x+3=0\end{array}\right.\)

\(\Rightarrow\left[\begin{array}{nghiempt}-2\\-3\end{array}\right.\)

Vậy x = -2 và x = -3

Answer 2

Ta có: \(x^2+5x+6=0\)

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

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

<=> \(\left[\begin{array}{nghiempt}x+2=0\\x+3=0\end{array}\right.\)

<=> \(\left[\begin{array}{nghiempt}x=-2\\x=-3\end{array}\right.\)

Vậy x\(\in\left\{-3;-2\right\}\)

Answer 3

x² + 5x + 6 = 0

 

⇒x²+ 2x + 3x + 6 = 0

⇒x ( x + 2 ) + 3 ( x + 2 ) = 0

⇒( x + 2 ) ( x + 3 ) = 0

⇒\(\left[\begin{array}{nghiempt}x+2=0\\x+3=0\end{array}\right.\)\(\Rightarrow\left[\begin{array}{nghiempt}x=-2\\x=-3\end{array}\right.\)

Vậy x = -2 và x = -3

Answer 4

 

x² + 5x + 6 = 0

⇒x² + 2x + 3x + 6 = 0

⇒x( x + 2 ) + 3( x + 2 ) = 0

⇒( x + 2 )( x + 3 ) = 0

⇒\(\left[\begin{array}{nghiempt}x+2=0\\x+3=0\end{array}\right.\)   ⇒\(\left[\begin{array}{nghiempt}x=-2\\y=-3\end{array}\right.\)

Vậy x = -2 và x = -3