15n^3分之4a^4b^2)/(35n^2分之-8a^2b^2)
=15n^3分之4a^4b^2)* (-8a^2b^2 分之35n^2)
=a^2/3n)*(7/-2)
=-7a^2/6n3ab^2分之a^2-4b^2乘以a-2b分之ab(过程)