Phân tích đa thức thành nhân tử:
a) \(\left(a+b\right)+\left(a+b\right)^2\)
b) \(4\left(x-y\right)+3\left(x-y\right)^2\)
c) \(\left(a-b\right)+\left(b-a\right)^2\)
d) \(\left(a-b\right)-\left(b-a\right)^2\)
e) \(a\left(a-b\right)^2-\left(b-a\right)^3\)
f) \(\left(y+z\right)\left(12x^2+6x\right)+\left(y-z\right)\left(12x^2+6x\right)\)