Question

Допоможіть !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

Answer 1

Ответ:

1) $7+m$

2) $\frac{1}{x -1}$

3) $\frac{5}{x+y}$

4) $\frac{5}{a-b}$

Объяснение:

1)

$\frac{49}{7-m} -\frac{m2}{7-m} =\frac{49-m^{2} }{7-m} =\frac{(7-m)(7+m)}{7-m} =7+m$

2)

$\frac{x+7}{x^{2} -1} -\frac{6}{x^{2} -1} =\frac{x+7-6}{x^{2} -1} =\frac{x+1}{x^{2} -1} =\frac{x+1}{(x-1)(x+1)} =\frac{1}{x -1}$

3)

$\frac{5x-2}{x^{2} -y^{2}} -\frac{5y-2}{x^{2} -y^{2}} =\frac{5x-2-(5y-2)}{x^{2} -y^{2}} =\frac{5x-2-5y+2}{x^{2} -y^{2}} =\frac{5x-5y}{x^{2} -y^{2}} =\frac{5(x-y)}{(x-y)(x+y)} =\frac{5}{x+y}$

4)

$\frac{3a-4b}{(a-b)^{2}} +\frac{2a-b}{(a-b)^{2}} =\frac{3a-4b+(2a-b)}{(a-b)^{2}} =\frac{3a-4b+2a-b}{(a-b)^{2}}= \frac{5a-5b}{(a-b)^{2}} =\frac{5(a-b)}{(a-b)(a-b)} =\frac{5}{a-b}$