5/12(a+b)²·(-a-b)³·[-3/4(a-b)³]·6/5(a-b)²
=5/12(a+b)²·[-(a+b)³]·[-3/4(a-b)³]·6/5(a-b)²
=[5/12×(-1)×(-3/4)×6/5][(a+b)^(2+3)][(a-b)^(3+2)]
=3/8(a+b)^5(a-b)^5