Question

va rog ajutor

imi trebuie in 30 min​

Answer 1

$9^n+3^{2n+1}+2*3^{2n+2}=198$

scriem $9^n$ ca fiind $3^{2n}$

$3^{2n}+3^{2n+1}+2*3^{2n+2}=198$

dam factor comun pe $3^{2n}$

$3^{2n}*(1+3+2*3^2)=198$

$3^{2n}*(1+3+2*9)=198$

$3^{2n}*(1+3+18)=198$

impartim prin 22

$3^{2n}*22=198$ | :22

$3^{2n}=9$

$3^{2n}=3^2$

$2n=2= > n=1$