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4a+3b=62 si 3a+4b=64. afla a si b

Răspuns :

Putem incepe prin a aduna cele doua ecuatii

4a+3b+3a+4b=62+64
7a+7b=126
7(a+b)=126
a+b=126/7
a+b=18

4a+3b=62 => a+a+a+a+b+b+b=62
a+3a+3b=62
a+3(a+b)=62
a+3·18=62
a+54=62
a=62-54
a=8

Din a=8 si 4a+3b=62 rezulta:
4·8+3b=62
32+3b=62
3b=62-32
3b=30
b=30/3
b=10

R:a=8, b=10

:)