9 la puterea 2x+1 minus 3 la puterea x+1 minus 6 = 0
Dau 60 pct!!!!

[tex]9^{2x+1}-3^{x+1}-6=0[/tex]
[tex]3^{2(2x+1)}-3^{x+1}-6=0[/tex]
[tex](3^{2x+1})^2-3^{x+1}-6=0[/tex]
Notam [tex]3^{2x+1} = y[/tex]
[tex]y^2-y-6=0[/tex]
Δ=b²-4ac= 25
[tex]y_{1,2}= \frac{-b+- \sqrt{delta} }{2a} [/tex]
[tex]y_1= \frac{1+5}{2} =3 [/tex]
[tex]y_2= \frac{1-5}{2} =-2 [/tex]
[tex]3^{2x+1} = 3[/tex]
[tex]2x+1=1=\ \textgreater \ x=0[/tex]
[tex]3^{2x+1}= -2[/tex]
-2<0 ==> Ø
==> S={0}