Question

Tìm nghiệm của các đa thức sau: D(x)=(x+1)(2x-7)

Answer 1

`D(x) = (x + 1)(2x - 7)`

`(x + 1)(2x - 7) = 0`

`<=>` $\left[\begin{matrix} x + 1 = 0\\ 2x - 7 = 0\end{matrix}\right.$

`<=>` $\left[\begin{matrix} x = -1\\ x = 7/2\end{matrix}\right.$

Vậy .......

Answer 2

\(D\left(x\right)=0\\ \Leftrightarrow\left(x+1\right)\left(2x-7\right)=0\\ \Leftrightarrow\left[{}\begin{matrix}x+1=0\\2x-7=0\end{matrix}\right.\\ \Leftrightarrow\left[{}\begin{matrix}x=-1\\x=\dfrac{7}{2}\end{matrix}\right.\)

Answer 3

D(x)=0⇔(x+1)(2x−7)=0⇔[x+1=02x−7=0⇔⎡⎣x=−1x=72