8.1÷[(297-3.5)÷97]
=8.1÷[(297-3.5)*79]
=8.1 ÷(29/9-49/18)
=8.1÷(58/18-49/18)
=8.1÷(9/18)
=8.1÷(1/2)
=8.1*2
=16.2