# How to prove ?

##
If # a/b = c/d = e/f #

prove that: # 1/27 ((a+b)/b + (c+d)/d + (e+f)/f)^3 = [(a+b)(c+d)(e+f)]/(bdf) #

If

prove that:

##### 1 Answer

Apr 12, 2018

We start by expanding the LHS of the equation.

Let

This can be further simplified:

We move to the RHS. Notice that

Indeed, both the LHS and RHS simplify to the same expression, so they must be equivalent.