b) \(\left(4x^2-9\right)=\left(2x+3\right)\left(5-x\right)\)
\(\Leftrightarrow4x^2-9=-2x^2+7x+15\)
\(\Leftrightarrow6x^2-7x-24=0\)
\(\Leftrightarrow\left(3x-8\right)\left(2x+3\right)=0\)
\(\Leftrightarrow\left[{}\begin{matrix}3x-8=0\\2x+3=0\end{matrix}\right.\)
\(\Leftrightarrow\left[{}\begin{matrix}3x=8\\2x=-3\end{matrix}\right.\)
\(\Leftrightarrow\left[{}\begin{matrix}x=\dfrac{8}{3}\\x=\dfrac{-3}{2}\end{matrix}\right.\)
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