I really need help with this question..
Which of the following are true for all real numbers a,b>0? For those that are not always true, give specific values of a,b>0 where they fail
(a) 1/a +1/b = 1/(a+b)
(b) 1/(a) + b = (1+b)/a
(c) 1/a +1/b = (a+b)/ab