Chapter 10 - Section 10.3 - Preparing to Do Analytic Proofs - Exercises - Page 474: 24

$ ((s+t)^2 + v^2)^2 =v^2 + (t-s)^2 $

We use the Pythagorean theorem: $(s+t)^2 + v^2 = \sqrt{v^2 + (t-s)^2} \\ ((s+t)^2 + v^2)^2 =v^2 + (t-s)^2 $ Thus meets the requirements of having no square roots or fractions and all three variables.