Răspuns :
4357+x+937=6251
4357+x=6251-937
4357+x=5314
x=5314-4357
x=957
7815-x+737=3511
7815-x=3511-737
7815-x=2774
x=7815-2774
x=5041
4357+x+937=6251
4357+x=6251-937
4357+x=5314
x=5314-4357
x=957
7815-x+737=3511
7815-x=3511-737
7815-x=2774
x=7815-2774
x=5041