Cho ad = bc

Câu hỏi: Cho ad = bc $(cd \ne 0; c^2 \ne 3d^2)$. Khi đó $\frac{{\text{a}}^{\text{2}}-{\text{3b}}^{\text{2}}}{{\text{c}}^{\text{2}}-{\text{3d}}^{\text{2}}}$  bằng?

A. $\frac{{\text{ab}}^{\text{2}}}{{\text{cd}}^{\text{2}}}$

B. $\frac{\text{ad}}{\text{bc}}$

C. $\frac{\text{ab}}{\text{cd}}$

D. $\frac{\text{cd}}{\text{ab}}$