(15ab/4)*[8/(9a^2b^2]=5*3ab/2^2*[2^3/(3^2a^2b^2)]
(15ab/4)*[8/(9a^2b^2]=5*3*2^3ab/(2^2*3^2a^2b^2)
(15ab/4)*[8/(9a^2b^2]=5*2^(3-2)/[(3^(2-1)a^(2-1)b^(2-1)]
(15ab/4)*[8/(9a^2b^2]=5*2^1/(3^1a^1b^1)
(15ab/4)*[8/(9a^2b^2]=5*2/(3ab)
(15ab/4)*[8/(9a^2b^2]=10/(3ab)