\(4x+by+4y+bx=\) \(\left(4x+4y\right)+\left(by+bx\right)\)
\(=\) \(4\left(x+y\right)+b\left(x+y\right)\)
\(=\left(4+b\right)\left(x+y\right)\)
\(2x^2+xy-2x-y=\) \(\left(2x^2+xy\right)-\left(2x+y\right)\)
\(=x\left(2x+y\right)-\left(2x+y\right)\)
\(=\left(x-1\right)\left(2x+y\right)\)