(1)5x-3.2=6.8, 5x-3.2+3.2=6.8+3.2, 5x=10, 5x÷5=10÷5, x=2;(2)12:x= 1 8 : 1 3 , 1 8 x=4, 1 8 x×8=4×8, x=32.