Question

tìm nghiệm của a,6x^2 - 2x

b,x^2 + 5x + 6

Answer 1

a) \(6x^2-2x=2x\left(3x-1\right)\)

\(2x\left(3x-1\right)=0\Leftrightarrow\left[{}\begin{matrix}2x=0\\3x-1=0\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=0\\x=\dfrac{1}{3}\end{matrix}\right.\)

Vậy \(S=\left\{0;\dfrac{1}{3}\right\}\)

b) \(x^2+5x+6=x^2+2x+3x+6=x\left(x+2\right)+3\left(x+2\right)=\left(x+3\right)\left(x+2\right)\)

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

Vậy \(S=\left\{-3;-2\right\}\)