Question

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Answer 1

$\dfrac{3}{x^2+14x+48}\div\dfrac{3}{10x+60}=\dfrac{3}{x^2+8x+6x+48}\cdot\dfrac{10x+60}{3}\\\\=\dfrac{1}{x(x+8)+6(x+8)}\cdot\dfrac{10(x+6)}{1}=\dfrac{10(x+6)}{(x+6)(x+8)}=\dfrac{10}{x+8}$

Answer: C. $\dfrac{10}{x+8}$