a, \(x^2+4x=x\left(x+4\right)\)
b, \(16x^2-9=\left(4x-3\right)\left(4x+3\right)\)
c, \(2x-2y+bx-by=2\left(x-y\right)+b\left(x-y\right)\)
\(=\left(b+2\right)\left(x-y\right)\)
d, \(x^2+4x-5=x^2+5x-x-5\)
\(=x\left(x+5\right)-\left(x+5\right)=\left(x-1\right)\left(x+5\right)\)
e, \(x^3+x+5x^2+5=x\left(x^2+1\right)+5\left(x^2+1\right)\)
\(=\left(x+5\right)\left(x^2+1\right)\)
f, \(x^2+2xy-9+y^2\)
\(=\left(x+y\right)^2-9\)
\(=\left(x+y+3\right)\left(x+y-3\right)\)
g, \(x^2-3xy-10y^2=x^2+2xy-5xy-10y^2\)
\(=x\left(x+2y\right)-5y\left(x+2y\right)\)
\(=\left(x-5y\right)\left(x+2y\right)\)