15 4/9+х+3 17/19=21 2/19
х=21 2/19-15 4/9-3 17/19
х=17 4/19-15 4/9
х=17 36/171-15 76/171
х=1 131/171
78+4129-3127=1080
23138/23=1006
1080*1006=1086480