a, $4x^2-6x$
$=2x(2x-3)$
b, $9x^4y^3+3x^2y^4$
$=3x^2y^3(3x^2+y)$
c, $3(x-y)-5x(y-x)$
$=3(x-y)+5x(x-y)$
$=(x-y)(3+5x)$
c,$x^3-2x^2+5x$
$=x(x^2-2x+5)$
d, $5(x+3y)-15x(x+3y)$
$=(x+3y)(5-15x)$
$=5(x+3y)(1-5x)$
e, $2x^2(x+1)+4(x+1)$
$=(x+1)(2x^2+4)$
$=(x+1)2(x^2+2)$