Question

$\frac{5}{ {m}^{2} - {n}^{2} } + \frac{4}{2m + 2n}$
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Answer 1

Ответ:

$\frac{5}{m^{2}-n^{2}  } + \frac{4}{2m+2n} = \frac{5}{(m-n)(m+n)} + \frac{4}{2(m+n)} =\\\frac{5*2+4*(m-n)}{2(m-n)(m+n)} = \frac{9}{m+n}$