Question

Tìm nghiệm của đa thức

B(x)=(x+2)(2x+5))

Mình cần gấp

Answer 1

\(B\left(x\right)=\left(x+2\right)\left(2x+5\right)=0\)

\(\Leftrightarrow\left[{}\begin{matrix}x+2=0\\2x+5=0\end{matrix}\right.\)

\(\Leftrightarrow\left[{}\begin{matrix}x=-2\\x=-\dfrac{5}{2}\end{matrix}\right.\)

Answer 2

\(B\left(x\right)=\left(x+2\right)\left(2x+5\right)=0\\ \Rightarrow\left[{}\begin{matrix}x+2=0\\2x+5=0\end{matrix}\right.\\ \Rightarrow\left[{}\begin{matrix}x=-2\\x=-\dfrac{5}{2}\end{matrix}\right.\)

Answer 3

Ta có:

\(B\left(x\right)=\left(x+2\right)\left(2x+5\right)\)

\(B\left(x\right)=0\Leftrightarrow\left(x+2\right)\left(2x+5\right)=0\)

\(\Leftrightarrow\left[{}\begin{matrix}x=-2\\x=\dfrac{-5}{2}\end{matrix}\right.\)

Vậy đa thức đã cho có nghiệm \(\left[{}\begin{matrix}x=-2\\x=\dfrac{-5}{2}\end{matrix}\right.\)

Answer 4

B(x)=0

\(\Leftrightarrow\left[{}\begin{matrix}x=-2\\x=-\dfrac{5}{2}\end{matrix}\right.\)