Question

4. Выполните сложение и вычитание дробей:​

Answer 1

а)

$\frac{b}{ {a}^{2} } + \frac{1}{a} = \frac{b + a}{a {}^{2} }$

б)

$\frac{ {x}^{2} - 3xy }{ {x}^{2} - {y}^{2} } - \frac{y}{x - y} = \frac{ {x}^{2} - 3xy}{(x - y)(x + y)} - \frac{y}{x - y} = \\ = \frac{ {x}^{2} - 3xy - y(x + y) }{(x - y)(x + y)} = \frac{ {x}^{2} - 3xy - xy - {y}^{2} }{(x - y)(x + y)} = \frac{ {x}^{2} - 4xy + {y}^{2} }{x {}^{2} - {y}^{2} }$