12x-3/4=0


2) 0,8+1/4x=0

3) 0,7x+1/5=0

4)2/5-10x=0

12x-3/4=012x=2/4x=3/4*1/12x=3/48=1/16x=1/162)0,8+1/4=00,8x=1/4x=1/4*10/8x=5/164)2/5-10x=010x=2/5x=2/5:10/1x=1/25или2/5-10x=010x=2/5x=0,4:10x=0,04