[poper]

ใช้โลปิตาลครับ
$$\lim_{x\to-2}\frac{4x+1}{-\frac{1}{3}(6-x)^{-\frac{2}{3}}-2(3x+7)^{-\frac{2}{3}}}$$
$$=\frac{-7}{-\frac{1}{3}(\frac{1}{4})-2}$$
$$=\frac{84}{25}$$