Question

Срочно и не трудно!
Даю 20 баллов.

Answer 1

$\displaystyle\bf\\1)\\\\\frac{2mb}{m^{2} - b^{2} } +\frac{m-b}{2m+2b}= \frac{2mb}{(m - b)\cdot(m+b) } +\frac{m-b}{2\cdot(m+b)}= \\\\\\=\frac{2mb\cdot 2+(m-b)\cdot(m-b)}{2\cdot(m-b)\cdot(m+b)} =\frac{4mb+m^{2} -2mb+b^{2} }{2\cdot(m-b)\cdot(m+b)} =\\\\\\=\frac{m^{2}+2mb+b^{2} }{2\cdot(m-b)\cdot(m+b)} =\frac{(m+b)^{2} }{2\cdot(m-b)\cdot(m+b)} =\frac{m+b}{2\cdot(m-b)}$

$\displaystyle\bf\\2)\\\\\frac{m+b}{2\cdot(m-b)} \cdot\frac{6m}{m+b} =\frac{3m}{m-b} \\\\\\3)\\\\\frac{3m}{m-b} +\frac{3b}{b-m} =\frac{3m}{m-b} -\frac{3b}{m-b} =\frac{3m-3b}{m-b}=\\\\\\=\frac{3\cdot(m-b)}{m-b}=3$