\(x\left(x-5\right)-3x+15=0\)
\(\Leftrightarrow x\left(x-5\right)-3\left(x-5\right)=0\)
\(\Leftrightarrow\left(x-3\right)\left(x-5\right)=0\)
\(\Leftrightarrow\left[{}\begin{matrix}x-3=0\\x-5=0\end{matrix}\right.\)
\(\Leftrightarrow\left[{}\begin{matrix}x=3\\x=5\end{matrix}\right.\)
Vậy \(S=\left\{3;5\right\}\)
`x (x - 5) - 3x + 15 = 0`
`<=> x(x-5) -3(x-5)=0`
`<=>(x-5)(x-3)=0`
`** x-5=0`
`=>x=5`
`** x-3=0`
`=>x=3`
\(x\left(x-5\right)-3x+15=0\)
\(\Leftrightarrow x^2-5x-3x+15=0\)
\(\Leftrightarrow x^2-8x+15=0\)
\(\Leftrightarrow\left(x-5\right)\left(x-3\right)=0\)
\(\Leftrightarrow\left[{}\begin{matrix}x-5=0\\x-3=0\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=5\\x=3\end{matrix}\right.\)
Vậy \(S=\left\{5;3\right\}\).
