1) (1.8+x)*21=71.4
2) 16(4x_3.4)=6.08
3) (x-1.25)*4.5=27
4)(x+19.64)*0.18=144
5)17(1.6-5x)=2.38
6) 9.66:(x+0.17)=23

1.8+x=71.4÷21
1.8+x=3.4
x=3.4-1.8
x=1.6

4x-3.4=6.08×16
4x-3.4=97.28
4x=97.28-3.4
4x=93.88
x=93.88÷4
x=23.47

x-1.25=27÷4.5
x-1.25=6
x=6-1.25
x=4.75