a) −|6.4−4x|=0
−|−4x+6.4|=0
|−4x+6.4|=0
−4x+6.4=0
x=1+3/5
б) |5x−1.4|=0
|5x−1.4|=0
5x−1.4=0
5x=1.4
x=7/25