x In Terms of a,b,c
Source:
February 1, 2009
Problem Statement
If \frac {xy}{x \plus{} y} \equal{} a, \frac {xz}{x \plus{} z} \equal{} b, \frac {yz}{y \plus{} z} \equal{} c, where are other than zero, then equals:
(A)\ \frac {abc}{ab \plus{} ac \plus{} bc} \qquad(B)\ \frac {2abc}{ab \plus{} bc \plus{} ac} \qquad(C)\ \frac {2abc}{ab \plus{} ac \minus{} bc}
(D)\ \frac {2abc}{ab \plus{} bc \minus{} ac} \qquad(E)\ \frac {2abc}{ac \plus{} bc \minus{} ab}