Question

Скоратите дробь, 12 баллов.
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Answer 1

1)

$\dfrac{x^2-4x}{x^2-x-12}=\dfrac{x(x-4)}{x^2+3x-4x-12}=\dfrac{x(x-4)}{x(x+3)-4(x+3)}=\\\\\\ =\dfrac{x(x-4)}{(x+3)(x-4)}=\bold{\dfrac{x}{x+3}}$

2)

$\dfrac{2x^2-11x+15}{x^2-9}=\dfrac{x(2x-5)-3(2x-5)}{(x-3)(x+3)}=\dfrac{(2x-5)(x-3)}{(x-3)(x+3)}=\\\\\\ =\bold{\dfrac{2x-5}{x+3}}$