(1)a-b/3a+3b ,a+b/5a-5b
(a-b)/(3a+3b)=5(a-b)^2/[15(a+b)(a-b)]
(a+b)/(5a-5b)=3(a+b)^2/[15(a+b)(a-b)]
(2)m-n ,mn/n-m
m-n=-(m-n)^2/(n-m)
mn/(n-m)=mn/(n-m)
(1)a-b/3a+3b ,a+b/5a-5b
(a-b)/(3a+3b)=5(a-b)^2/[15(a+b)(a-b)]
(a+b)/(5a-5b)=3(a+b)^2/[15(a+b)(a-b)]
(2)m-n ,mn/n-m
m-n=-(m-n)^2/(n-m)
mn/(n-m)=mn/(n-m)