90.1)(2x+1)÷1,3=2,5÷0,652x+1=(1,3×2,5)÷0,65 2x+1=52x=5-12x=4x=22)3,25÷(4x-1,9)=13÷0,44x-1,9=(3,25×0,4)÷134x-19=0,14x=0,1+194×=19,1x=19,1÷4x=4,7753)2,7÷9=(1+1÷5)÷(3x+1)3x+1=9×(1+1÷5)÷2,73x+1=43x=4-13x=3x=14)(1+4÷5)÷2,5=7,2÷(6x+1)6x+1=2,5×7,2÷(1+4÷5)6x+1=106x=10-16x=9x=1,55)6÷(1+4÷5)=(3x+0,6)÷2,883x+0,6=6×2,88÷(1+4÷5)3x+0,6=9,63x=9,6÷0,63x=1,6x=5+1/36)8÷0,75=0,6÷(x-2,8)x-2,8=0,6×0,75÷8 x-2,8=0,45÷8x=2,85625