Răspuns :
a-b=87
a:b=5 rest 15
a=5b+15
5b+15-b=87
4b+15=87
4b=87-15
4b=72
b=72:4
b=18
a=5b+15
a=5x18+15
a=90+15
a=105
105-18=87(verificare)
a:b=5 rest 15
a=5b+15
5b+15-b=87
4b+15=87
4b=87-15
4b=72
b=72:4
b=18
a=5b+15
a=5x18+15
a=90+15
a=105
105-18=87(verificare)