b: \(\dfrac{2x^3+3x^2-2x-1}{2x+3}\)
\(=\dfrac{2x^3+3x^2-2x-3+2}{2x+3}\)
\(=\dfrac{x^2\left(2x+3\right)-\left(2x+3\right)+2}{2x+3}\)
\(=x^2-1+\dfrac{2}{2x+3}\)
vậy: \(2x^3+3x^2-2x-1=\left(x^2-1\right)\left(2x+3\right)+2\)
c: \(3x\left(x-2\right)+5\left(2-x\right)=0\)
=>3x(x-2)-5(x-2)=0
=>(x-2)(3x-5)=0
=>\(\left[{}\begin{matrix}x-2=0\\3x-5=0\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=2\\x=\dfrac{5}{3}\end{matrix}\right.\)
Giúp mình với nhanh nhé c2 và câu 3 ạ