300–x*5=210 (300–x)*5=210 (150–20):x=65 (x+4)*7=350 (300–18)*x=1410 5*x–600=900
Х*5 = 300 - 210 = 90 х=90*5 = 18 300-х = 210:5= 42 х=300-42=258 130:х=65 х=130:65=2 х+4=350:7=50 х=50-4=46 282*х=1410 х=1410:282=5 5*х=600+900=1500 х=1500:5=300