(0,2х+0,4х)×3,5=6,3 =3,2:3,3 =(2,4×3,3)=74
(0,2х+0,4х)×3,5=74 0.6х×3.5=74 0.6×3.5=2.1х 2.1х=74 х=74÷2.1 х=35.2381