Question

1. Выполните сложение и вычитание дробей:
1) 1/2a+1/a

2) 3/3-y-/y^2-9

Answer 1

1)

$\tt \displaystyle \frac1{2a} +\frac1a ^{(2} =\frac{1+2}{2a} =\frac3{2a}$

Ответ: $\tt \displaystyle \frac3{2a}$

2)

$\tt \displaystyle \frac3{3-y} -\frac{y}{y^2 -9} =\frac{-3}{y-3} ^{(\, (y+3)} -\frac{y}{(y-3)(y+3)} =\\ \\ =\frac{-3y-9-y}{(y-3)(y+3)} =\frac{-(4y+9)}{y^2 -9} =-\frac{4y+9}{y^2 -9}$

Ответ:  $\tt \displaystyle -\frac{4y+9}{y^2 -9}$