( 4又3/7+ 7又3/4/ )/ (5/7+1又1/4)
麻烦写出 过程
原式=(31/7+31/4)/(5/7+5/4)
=31x(1/7+1/4)/5x(1/7+1/4)
=31/5
原式=(31/7+31/4)(5/7+5/4)
=31*5*(1/7+1/4)(1/7+1/4)
=155*121/784
=18755/784