Question

Решите систему уравнений х+у =5 3х-2у=3

Answer 1

$\tt\displaystyle \left \{ {{x+y=5} \atop {3x-2y=3}} \right. \Longrightarrow \left \{ {{x=5-y} \atop {3x-2y=3}} \right. \\\\3(5-y)-2y=3\\15-3y-2y=3\\15-5y=3\\5y=15-3\\5y=12\\y=12:5\\\bold{y=2,4}\\\\\\x=5-y\\x=5-2,4\\\bold{x=2,6}$

ответ: (2,6; 2,4)

Answer 2

(2,6; 2,4).

Объяснение:

$\left \{ \begin{array}{lcl} {{x+y=5|*2,} \\ {3x-2y=3};} \end{array} \Leftrightarrow\left \{ \begin{array}{lcl} {{2x+2y=10} \\ {3x-2y=3}} \end{array} \right.\right.\Leftrightarrow\left \{ \begin{array}{lcl} {{x+y=5,} \\ {5x=13;}} \end{array} \right.\Leftrightarrow$

$\Leftrightarrow\left \{ \begin{array}{lcl} {{y=5-x,} \\ {x=13:5;}} \end{array} \right.\Leftrightarrow\left \{ \begin{array}{lcl} {{y=5-2,6,} \\ {x=2,6;}} \end{array} \right.\Leftrightarrow\left \{ \begin{array}{lcl} {{y=2,4} \\ {x=2,6.}} \end{array} \right.$