Язапуталась! (12+7х)*2=24 (63-9х): 3=15 (49-11х): 3=9

(12+7х)*2=24
24+14х-24=0
14х=0
х=0

(63-9х):3=15
21-3х-15=0
6-3х=0
3х=6
х=2

(49-11х):3=9
49-11х=27
22=11х
х=2

(12+7х)×2=24                     (63-9х):3=15                         (49-11х):3=9
12+7х=24:2                        63-9х=15×3                          49-11х=9×3
12+7х=12                           63-9х=45                              49-11х=27
7х=12-12                            9х=63-45                              11х=49-27
7х=0                                  9х=18                                    11х=22
х=0:7                                 х=18:9                                    х=22:11
х=0                                    х=2                                         х=2
(12+7×0)×2=24                (63-9×2):3=15                        (49-11×2):3=9