Question

Rezolvati ecuatia 3ˣ⁺¹+3²⁻ˣ=12
Eu am inceput asa 3ˣ.3+3².3⁻ˣ=12. Multumesc. x+1 si 2-x sunt la exponent.

Answer 1

3ˣ.3+3².3⁻ˣ=12
3*3^x +(3^2)/(3^x)=12
3^x=t
3t+9/t=12  l xt
3t^2 +9=12t
3t^2 -12t+9=0
Impartim prin 3:
t^2 -4t+3=0
(t-1)(t-3)=0
t=1 sau t=3
3^x=1, x=0
3^x=3, x=1