\Lim x^2} - 5x + 6) / x^3} - 1/ 4 - {x^2 bằng7/39\(\mathop {\lim }\limits_{x \to 2} \frac{{({x^2} - 5x + 6)({x^3} - 1)}}{{4 - {x^2}}}\) bằng\( - \frac{7}{4}\)\(\frac{1}{4}\)\(\frac{7}{4}\)\(0\)Giải thíchChọn C