Question

a+b/ab para a=1/2 e b=-2/3

Answer 1

$\dfrac{a+b}{ab}\\\\\\ =\dfrac{\frac{1}{2}+\left(-\frac{2}{3} \right )}{\frac{1}{2}\cdot \left(-\,\frac{2}{3} \right )}\\\\\\ =\dfrac{\frac{1}{2}-\frac{2}{3}}{\frac{1\,\cdot\, (-2)}{2\,\cdot\, 3}}\\\\\\ =\dfrac{\frac{3}{6}-\frac{4}{6}}{\left(-\,\frac{2}{6} \right )}\\\\\\ =\dfrac{\frac{3-4}{6}}{\left(-\,\frac{2}{6} \right )}\\\\\\ =\dfrac{\left(-\,\frac{1}{6} \right )}{\left(-\,\frac{2}{6} \right )}\\\\\\=\dfrac{\left(\frac{1}{6}\right)}{\left(\frac{2}{6}\right)}\\\\\\=\dfrac{1}{6}\cdot \dfrac{6}{2}=\dfrac{1}{2}$


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