\(5\left(x-3\right)-x\left(3-x\right)=5\left(x-3\right)+x\left(x-3\right)=\left(x-3\right)\left(x+5\right)\)
\(5\left(x-3\right)+x\left(x-3\right)=\left(5+x\right)\left(x-3\right)\)
5.(x - 3) - x.(3 - x) = 5.(x - 3) + x.(x - 3) = (5 + x).(x - 3)
= \(\left(x+5\right)\left(x-3\right)\)