Răspuns :
a+b=77
b-a=11
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2b=77+11, 2b=88, b=88:2, b=44
a=77-44 , a=33
b-a=11
-----------
2b=77+11, 2b=88, b=88:2, b=44
a=77-44 , a=33
a+b=77
-a+b=11
a cu -a egal zero
b+b=2b
2b=77+11
2b=88
b=88:2
b=44
a+44=77
a=77-44
a=33
Verificare:
a+b=33+44=77
b-a=44-33=11
-a+b=11
a cu -a egal zero
b+b=2b
2b=77+11
2b=88
b=88:2
b=44
a+44=77
a=77-44
a=33
Verificare:
a+b=33+44=77
b-a=44-33=11