(1)2.5x+1.5x=4.8, 4x÷4=4.8÷4, x=1.2;(2) 2 5 x+120× 1 5 =24, 2 5 x+24-24=24-24, 2 5 x÷ 2 5 =0÷ 2 5 , x=0;(3)x×3.6=1 2 5 ×3, 3.6x÷3.6= 21 5 ÷3.6, x=1 1 6 .