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rezolvati in R sistemu
3x+5y=21
2x-y=1


Răspuns :

2x-y=1 => y=2x-1 si inlocuim in prima ecuatie
3x+5(2x-1)=21 => 13x=26 => x=2 => y=2*2-1=3
3x+5y=21
2x-y=1   /*5

3x+5y=21
10x-5y=5
========(+)
13x   /  =26
x=26:13
x=2

2*2-y=1
4-y=1
y=3