（-4/3a^2b^2)(3/2a^2+ab-3/5b^2)/(4/3a^2b^2)
=[（-4/3a^2b^2)/(4/3a^2b^2)](3/2a^2+ab-3/5b^2)
=-(3/2a^2+ab-3/5b^2)
=-3/2a^2-ab+3/5b^2