\(a,-3x^2+5x=0\)
\(\Rightarrow x\left(5-3x\right)=0\)
\(\Rightarrow\left[{}\begin{matrix}x=0\\5-3x=0\end{matrix}\right.\)
\(\Rightarrow\left[{}\begin{matrix}x=0\\x=\dfrac{3}{5}\end{matrix}\right.\)
Vậy................
\(b,x^2-5x-24=0\)
\(\Rightarrow x^2-8x+3x-24=0\)
\(\Rightarrow\left(x^2+3x\right)-\left(8x+24\right)=0\)
\(\Rightarrow x\left(x+3\right)-8\left(x+3\right)=0\)
\(\Rightarrow\left(x-8\right)\left(x+3\right)=0\)
\(\Rightarrow\left[{}\begin{matrix}x-8=0\\x+3=0\end{matrix}\right.\)
\(\Rightarrow\left[{}\begin{matrix}x=8\\x=-3\end{matrix}\right.\)
Vậy........................
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