Răspuns :
[tex]x-2*y +13=52 \\ 3*x-6*y+1 =? \\ x-2y =52-13 =\ \textgreater \ x-2y = 39 =\ \textgreater \ x = 39 +2y \\ 3x -6y +1 = 3 (39 +2y) -6y +1= 117 +6y -6y +1=\ \textgreater \ \\ 117 +1 =118 =\ \textgreater \ 3x -6y+1=118[/tex]
x-2y=39⇒x=2y+39;
⇒3[2y+39]-6y+1
⇒6y+117-6y+1⇒se reduce 6y cu 6y;
⇒117+1=118;
⇒3[2y+39]-6y+1
⇒6y+117-6y+1⇒se reduce 6y cu 6y;
⇒117+1=118;