1、[(a^2-b^2)/ab]÷(a-b)^2
=[(a+b)(a-b)/ab]÷(a-b)^2
=(a+b)/[ab(a-b)];
2、(3y^2/2x^2)×(6x/5y)÷(21x^2/10y)
=(9y/5x)÷(21x^2/10y)
=6y^2/7x^3.
1、[(a^2-b^2)/ab]÷(a-b)^2
=[(a+b)(a-b)/ab]÷(a-b)^2
=(a+b)/[ab(a-b)];
2、(3y^2/2x^2)×(6x/5y)÷(21x^2/10y)
=(9y/5x)÷(21x^2/10y)
=6y^2/7x^3.