Beispiel Nr: 17
$(ax+ b)\cdot (ax - b) = a^{2}x^{2} - b^{2} \\ (a + b)\cdot (a - b)\\ \textbf{Gegeben:} \\ (\frac{2}{5}x + \frac{1}{3})(\frac{2}{5}x - \frac{1}{3})\\ \\ \textbf{Rechnung:} \\\text{3. Binomische Formel} \\(\frac{2}{5}x+\frac{1}{3})(\frac{2}{5}x-\frac{1}{3})=\frac{2}{5}^{2}x^{2}-\frac{1}{3}^{2} \\(\frac{2}{5}x+\frac{1}{3})(\frac{2}{5} x-\frac{1}{3})= \frac{4}{25}x^2-\frac{1}{9} $