Make a substitution to find two exact real solutions
to the equation $(x + 3)^4 + (x + 5) ^4 = 20.$
know ... ?
Frequently mathematicians spend their time stuck wondering how
to solve equations or problems. One way of cracking a tough problem
is to make a transformation to turn it into a more familiar form
which allows the solution to proceed. Finding good substitutions or
transformations is one of the more creative aspects of