a) 3x+9y
=3(x+3y)
b) 4x2-16xy
=4x(x-4y)
c) x2-6x+9
=(x-3)2
d) 4y2-36
=(2y-6)(2y+6)
e) 4y2-4
=(2y-2)(2y+2)
f) 5a2-9
=\(\left(\sqrt{5}a-3\right)\left(\sqrt{5}a+3\right)\)
g) x3-2x2+x
=x(x2-2x+1)
=x(x-1)2
h) 5xy3-10xy2+5xy
=5xy(y2-2y+1)
=5xy(y-1)2
i) 12x2y+12xy+3y
=3y(4x2+4x+1)
=3y(2x+1)2
k) 5x-5y+y2-xy
=(5x-5y)+(y2-xy)
=5(x-y)-y(x-y)
=(x-y)(5-y)
#H