Question

спростити вираз
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Answer 1

$( \frac{b}{a(3-a)(3+a)} - \frac{1}{a(a+3)} - \frac{3}{b(3-a)(3+a)} )* \frac{ab(a-3)(a+3)}{(b-3)(b-3)} = \\ \\ \frac{b^2-b(3-a)-3a}{ab(3-a)(3+a)} * \frac{ab(a-3)(a+3)}{(b-3)(b-3)} = \\ \\ \frac{b^2-3b+ab-3a}{ab(3-a)(3+a)} * \frac{ab(a-3)(a+3)}{(b-3)(b-3)} = \\ \\ \frac{b(b-3)+a(b-3)}{(b-3)(3-b)} = \frac{(b-3)(a+b)}{(b-3)(3-b)} = \frac{a+b}{3-b \\ \\ }$