Question

{x+2y=3
{3x-y=5 stie cineva sa o rezolve este sistem

Answer 1

[tex]x+2y=3(1)\\3x-y=5\\(1)\cdot3\\3(x+2y)=3\cdot3\\3x+6y=9(3)\\(3)-(2)\\ (3x+6y)-(3x-y)=9-5\\7y=4\\y=\frac{4}{7}\\Inlocuim\ pe\ y\ in\ relatia\ (1)\\ x+2\cdot\frac{4}{7}=3\\x+\frac{2\cdot4}{7}=3\\ampificam\ pe\ x\ cu\ 7\\ \frac{7x}{7}+\frac{8}{7}=3\\\frac{7x+8}{7}=3\\7x+8=3\cdot7\\7x+8=21\\ 7x=21-8\\7x=13\\x=\frac{13}{7}[/tex]