X*8+(560-320)=70*3+490:7
8х+240=210+70 8х=280-240 8х=40 х=40:8 х=5
8х+240=210+70
8х=210+70-240
8х=40
х=40:8
х=5
5*8+(560-320)=70*3+490:7
40+240=210+70
280=280
Спасибо