5a/3(b^2)c - 7b/6ac^2 + 11c/4(a^2)b
=(5a*4a^2c-7b*2ab^2+11c*3bc^2)/(12a^2b^2c^2)
=(20a^3c-14ab^3+33bc^3)/(12a^2b^2c^2)