1.(85-15)/x=35, 2. x*8=810-90, 3. x/(320/4)=6
(85-15):х=35 70:х=35 х=70:35 х=2 Х•8=810-90 х•8=720 х=720:8 х=90 х:(320:4)=6 х:80=6 х=6•80 х=480
2.8х=720 х=90 3 3.х=480