Chapter 14.1, Problem 43ES

Use a CAS to evaluate the iterated integrals

${\displaystyle {\int }_0^1{\displaystyle {\int }_0^1\frac{y-x}{{\left(x+y\right)}^3}dxdy\text{and}}}{\displaystyle {\int }_0^1{\displaystyle {\int }_0^1\frac{y-x}{{\left(x+y\right)}^3}dydx}}$

Does this contradict Theorem 14.1.3? Explain.