Объяснение:

[tex]( \frac{a}{d} - \frac{d}{a} ) \times \frac{5ad}{a + d} =\left(\frac{aa}{ad}-\frac{dd}{ad}\right)\times \left(\frac{5ad}{a+d}\right)=\frac{aa-dd}{ad}\times \left(\frac{5ad}{a+d}\right) =\frac{aa-dd}{ad}\times \left(\frac{5ad}{a+d}\right) =\frac{a^{2}-d^{2}}{ad}\times \left(\frac{5ad}{a+d}\right) =\frac{\left(a^{2}-d^{2}\right)\times 5ad}{ad\left(a+d\right)} =\frac{5\left(a^{2}-d^{2}\right)}{a+d} =\frac{5\left(a+d\right)\left(a-d\right)}{a+d} =5\left(a-d\right) [/tex]