[tex] \frac{a+b+c+d}{4} =6,6=\ \textgreater \ a+b+c+d=6,6*4=\ \textgreater \ a+b+c+d=26,4 \\ b=a+3,6 \\ c=2a \\ d= \frac{a+b}{2} =\ \textgreater \ d=\frac{a+a+3,6}{2} =\ \textgreater \ d= \frac{2a+3,6}{2} =\ \textgreater \ d=a+1,8 \\ a+a+3,6+2a+a+1,8=26,4 \\ 5a=26,4-5,4 \\ a=21:5=\ \textgreater \ a=4,2 \\ b=4,2+3,6=\ \textgreater \ b=7,8 \\ c=2*4,2=\ \textgreater \ c=8,4 \\ d=4,2+1,8=\ \textgreater \ d=6 \\ \\ verificare: \frac{4,2+7,8+8,4+6}{4} = \frac{26,4}{4} =6,6[/tex]
