Răspuns :
a+b=34
a+x+b+x=34+2x
15+23=34+2x
38=34+2x
2x=38-34
2x=4
x=2
a+x=15
a=15-2=13
b+x=32
b=23-2=21
a+x+b+x=34+2x
15+23=34+2x
38=34+2x
2x=38-34
2x=4
x=2
a+x=15
a=15-2=13
b+x=32
b=23-2=21
15+23=38 suma numerelor la care s-a adunat
38-34=4 suma celor doua nr identice adunate
4:2=2 numarul adunat
15-2=13 un numar
23-2=21 celalalt nr
Proba: 13+21=34
38-34=4 suma celor doua nr identice adunate
4:2=2 numarul adunat
15-2=13 un numar
23-2=21 celalalt nr
Proba: 13+21=34