Представьте в виде дроби: a) \(\frac{a}{7} + \frac{b}{7}\); в) \(\frac{n}{3k} - \frac{n-2k}{3k}\); б) \(\frac{4x^2}{b} - \frac{9x^2}{b}\); г) \(\frac{10a - 1}{6a} - \frac{7a+5}{6a}\).

a) \(\frac{a}{7} + \frac{b}{7}\) = \(\frac{a+b}{7}\)

Ответ: \(\frac{a+b}{7}\)

в) \(\frac{n}{3k} - \frac{n-2k}{3k}\) = \(\frac{n - n + 2k}{3k}\) = \(\frac{2k}{3k}\) = \(\frac{2}{3}\)

Ответ: \(\frac{2}{3}\)

б) \(\frac{4x^2}{b} - \frac{9x^2}{b}\) = \(\frac{4x^2 - 9x^2}{b}\) = \(\frac{-5x^2}{b}\)

Ответ: \(\frac{-5x^2}{b}\)

г) \(\frac{10a - 1}{6a} - \frac{7a+5}{6a}\) = \(\frac{10a - 1 - 7a - 5}{6a}\) = \(\frac{3a - 6}{6a}\) = \(\frac{3(a - 2)}{6a}\) = \(\frac{a-2}{2a}\)

Ответ: \(\frac{a-2}{2a}\)