math科(SOS)

A=?
8*6*D*/A=B*C*5
A=86D/BC5
-------------------------------------
B=?
86D/A=BC5
(86*5*C*D)/A=B
B=(430CD)/A
-------------------------------------
C=?
86*D/A=B*C*5
(86*5*B*D)/A=C
C=(430BD)/A
-------------------------------------
D=?
86*D/A=B*C*5
86*D=A*B*C*5
D=(A*B*C*5)/86
D=5ABC/86
-------------------------------------

A=86D/BC5
B=86D/AC5
C=86D/AB5
D=ABC5/86