Question

Решить систему уравнения:(2x+3y=3;(x-2y=5;

Answer 1

выражаем х через у,х=5+2у

2(5+2у)+3у=3

7у=3-10

у=-1

х=5+2(-1)=3

ответ:(3;-1)

Answer 2

$\left \{ {{2x+3y=3;} \atop {x-2y=5;}} \right.\\ \left \{ {{2x+3y=3;} \atop {x=2y+5;}} \right.\\ \left \{ {{2(2y+5)+3y=3;} \atop {x=2y+5;}} \right.\\ \left \{ {{4y+10+3y=3;} \atop {x=2y+5;}} \right.\\ \left \{ {{7y+10=3;} \atop {x=2y+5;}} \right.\\ \left \{ {{7y=3-10;} \atop {x=2y+5;}} \right.\\ \left \{ {{7y=-7;} \atop {x=2y+5;}} \right.\\ \left \{ {{y=-1;} \atop {x=2y+5;}} \right.\\ \left \{ {{y=-1;} \atop {x=2*(-1)+5;}} \right.\\ \left \{ {{y=-1;} \atop {x=3}} \right.$

ответ: (3;-1)