已知[12÷(?-6)×3又3分之1-9]+1900=1981.是几谢谢了,

问题描述:

已知[12÷(?-6)×3又3分之1-9]+1900=1981.是几谢谢了,

12÷(X-6)*10/3-9=81 12÷(X-6)*10/3=90 12÷(X-6) =90*3/10 12÷(X-6) =27 X-6=4/9 X=6又9分之4