Răspuns :
5x+5y+7z=196 5x+5y+7z=196 7x+7y+5z= ?
z= 3 5(x+ y)+7·3=196 7(x+y)+5·3=
7x+7y+5z= ? 5(x+ y)+21=196 7·35+15=
5(x+y) =196- 21 245+ 15=
5(x+y) =175 I : 5 260
x+y = 35
z= 3 5(x+ y)+7·3=196 7(x+y)+5·3=
7x+7y+5z= ? 5(x+ y)+21=196 7·35+15=
5(x+y) =196- 21 245+ 15=
5(x+y) =175 I : 5 260
x+y = 35
[tex]5x+5y+7*3=196 \\ 5(x+y)=196-21 \\ x+y=175:5 \\ x+y=35 \\ 7x+7y+5z=7(x+y)+5*3=7*35+15=260[/tex]