Question

Прошу помочь привести к общему знаменателю. 20 баллов​

Answer 1

$1)\ \ \dfrac{3b}{b-2}=\dfrac{3b\, (b+2)}{b^2-4}\ \ ,\ \ \ \ \dfrac{4}{b^2-4}\\\\\\2)\ \ \dfrac{7a}{x^2-9}\ \ ,\ \ \ \dfrac{a}{x+3}=\dfrac{a\, (x-3)}{x^2-9}\\\\\\3)\ \ \dfrac{1}{1-a}=\dfrac{1+a}{1-a^2}\ \ ,\ \ \dfrac{2a}{1+a}=\dfrac{2a\, (1-a)}{1-a^2}\ \ ,\ \ \dfrac{a^2}{1-a^2}$

$4)\ \ \dfrac{6x}{x-y}=\dfrac{6x\, (x+y)}{x^2-y^2}\ \ ,\ \ \dfrac{7xy}{x+y}=\dfrac{7xy\, (x-y)}{x^2-y^2}\ \ ,\ \ \dfrac{3}{x^2-y^2}$

Answer 2

1. 3b/(b-2)=3b*(b+2)/(b²-4)=(3b²+6b)/(b²-4); 4/(b²-4);

2. a/(х+3)=а*(х-3)/(х²-9)=(ах-3а)/(х²-9); 7а/(х²-9);

3. (1+а)/(1-а²); 2а*(1-а)/(1-а²)=(2а-2а²)/(1-а²); а²(1-а²);

4. (6х²-6ху)/(х²-у²); 7ху*(х-у)/(х²-у²)=(7х²у-7ху² )/(х²-у²);  3/х²-у²);