номер 3 решите пожалуйста

140 и 1400:20
400*6 и 40
3620 и 5310

300 и 15000
20-5 и 200-50
170 и 2500

70*2+х=3500+120                  х+2400:60=310+5000
140+х=3620                             х+40=5310
х=3620-140                              х=5310-40
х=3480                                      х=5270


9000:30-х=300-130                      7500*2 -х=1250*2
300-х=170                                    15000 -х=2500
 х=300-170                                    х=15000-2500
 х=130                                            х=12500