6分之5×4.7+5.3÷5分之6
=5/6×(4.7+5.3)
=5/6×10
=25/3
12减4分之3×21分之20减7分之2
=12-(5/7+2/7)
=12-1
=11
2分之1+2×=6.5
2x=6
x=3