I am having trouble simplifying a problem involving the chain rule and the product rule.

The question is:

Differentiate y=(x-1)^6(x+1)^4

My working is as follow:

dy/dx = (x-1)^6*4(x+1)^3*1+(x+1)^4*6(x-1)^5*1

4(x+1)^3(x-1)^6 + 6(x+1)^4(x-1)^5

This is where I am stuck. The book says the answer is:

2(x-1)^5(x+1)^3(5x+1)

If someone can please help me go from my stuck point to the answer I would be very grateful.