[填空题]
You have three tuning)lyu/p*pzl-i f)iyju*eq h2k 1tyb*kki+b 52 borks, A, B, and C. Fork B has a frequency of 441 Hz; when A and B are sounded together, a beat frequency of 3 Hz is heard. When B and C are sounded together, the beat frequency is 4 Hz. What are the possible frequencies of A and C? What beat frequen )bbykteh 1 q22*i uy5+ijk*bkcies are possible when A and C are sounded together?$f_A$ = Hz or Hz
$f_C$ = Hz or Hz
|$f_A$-$f_C$| Hz or Hz