(a+b)2-(c-d)2 / (a+c)2-(b-d)2
a[tex] \frac{a^{2} + b^{2} + 2ab - c^{2} + 2cd - d^{2}}{a^{2} +c^{2}+2ac - b^{2} -d^{2} + 2bd} [/tex]
[tex]-\frac{2ab + 2cd}{2ac+ 2bd}[/tex]
[tex]-\frac{2(ab+cd)}{2(ac+bd)}[/tex]
[tex]-\frac{(ab+cd)}{(ac+bd)}[/tex]
Espero que te siva de ayuda.
