1：1.8+x =2.4 x = 2.4-1.8 x = 0.6 2：x÷2.8=0.4 x = 0.4 X 2.8 x = 1.12 3 ：4x-2.5×0.5 =3.75 4x = 3.75 + 2.5 X0.5 4x = 5 x=1.25
