Question

determinati numarul x si y stind ca suma lor este 23 iar 3.x+7.y=113

Answer 1

 x+y= 23  / * (-3)
3x+7y=113

-3x-3y= -69 +
3x+7y=113
_________
/  4y=44
     y=11

x+y= 23
x= 23-11
     x=12

Answer 2

[tex] \left \{ {{x+y=23}|(-7)\ \textless \ =\ \textgreater \ -7x-7y=-161 \atop {3x+7y=113|1\ \textless \ =\ \textgreater \ 3x+7y=113}} \right. \\ ----------\\ -4x=-48=\ \textgreater \ x=12\\ x+y=23\ \textless \ =\ \textgreater \ 12+y=23=\ \textgreater \ y=11\\\\ [/tex]