d)\(x^2-9x=x\left(x-9\right)\)
e)\(6x^2+13x+5=6x^2+10x+3x+5=2x\left(3x+5\right)+\left(3x+5\right)=\left(2x+1\right)\left(3x+5\right)\)
f)\(5x^2-12x+4=5x^2-10x-2x+4=5x\left(x-2\right)-2\left(x-2\right)=\left(5x-2\right)\left(x-2\right)\)
g)\(x^2+x+30=x^2+5x+6x+30=x\left(x+5\right)+6\left(x+5\right)=\left(x+6\right)\left(x+5\right)\)