`a)2(x+3)-x(x+3)=0`
`=>(x+3)(2-x)=0`
\(\left[{}\begin{matrix}x+3=0\Rightarrow x=-3\\2-x=0\Rightarrow x=2\end{matrix}\right.\)
`b)x^2 - 10x =-25`
`=>x^2 - 10x +25=0`
`=>(x-5)^2 =0`
`=>x-5=0`
`=>x=5`
a.
\(2\left(x+3\right)-x\left(x+3\right)=0\)
\(\Leftrightarrow\left(x+3\right)\left(2-x\right)=0\)
\(\Leftrightarrow\left[{}\begin{matrix}x+3=0\\2-x=0\end{matrix}\right.\)
\(\Leftrightarrow\left[{}\begin{matrix}x=-3\\x=2\end{matrix}\right.\)
b.
\(x^2-10x=-25\)
\(\Leftrightarrow x^2-10x+25=0\)
\(\Leftrightarrow\left(x-5\right)^2=0\)
\(\Leftrightarrow x-5=0\)
\(\Leftrightarrow x=5\)
