5/9×86又7/11+5/11×1/9+4×5/11=5/9x81+5/9x5又7/11+5/11x1/9+4x5/11=45+5/9x62/11+5/11x1/9+5/11x4=45+5/11x62/9+5/11x1/9+5/11x4=45+5/11x(62/9+1/9+4)=45+5/11x11=45+5=49如果本题有什么不明白可以追问,...