a) 5ax²+4ax³+10a²x+8a²x²=ax²(5+4x)+2a²x(5+4x)=ax(5+4x)(x+2a)
b) 12x²y³+4x²y+9y²z²+3z²=4x²y(3y²+1)+3z²(3y²+1)=(3y²+1)(4x²y+3z²)
c) 5xy+2x²y+10x²y²+4x³y²=xy(5+2x)+2x²y²(5+2x)=xy(5+2x)(1+2xy)
d) 2x²+3a²x-4ax-6a³=2x(x-2a)+3a²(x-2a)=(x-2a)(2x+3a²)