Question

номер 813 а)б) срочно

Answer 1

$a) frac{4}{x-y} = frac{4(x-y)}{(x-y)^{2}} = frac{4x-4y}{(x-y)^{2}}$
$b) frac{x}{a-b} = frac{x(a+b)}{(a-b)(a+b)} = frac{xa+ab}{a^{2}-b^{2}}$

Answer 2

Знаю букву б):

x(а+b)/a^2-b^2 = ax+bx/a^2-b^2