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Решите задачу:

$1) \frac{x^2+3x}{3a+ax} = \frac{x(x+3)}{a(x+3)} = \frac{x}{a} \\ \\ 2) \frac{b^2}{b^2+bc} = \frac{b*b}{b(b+c)} = \frac{b}{b+c} \\ \\ 3) \frac{2a+4}{a^2-4} = \frac{2(a+2)}{a^2-2^2} = \frac{2(a+2)}{(a-2)(a+2)} = \frac{2}{a-2} \\ \\ 4) \frac{x^2-y^2}{x^2-xy} = \frac{(x-y)(x+y)}{x(x-y)} = \frac{x+y}{x} = \frac{x}{x} + \frac{y}{x} = 1+ \frac{y}{x} \\ \\$