9^(n+1) - 3^2n x 5=
=3^(2n+2) - 3^2n x 5=
=3^2n*(3^2 - 5)=
=3^2n*(9 - 5)=
=3^2n*4=
=3^2n*2^2=
=(3^n*2)^2 deci patrat perfect
2^3x +4^x * 2^(x+2) + 8^(x+1) = 832
2^3x +2^2x * 2^(x+2) + 8^(x+1) = 832
2^3x +2^(3x+2) + 2^(3x+3) = 832
2^3x*(2^0+2^2+2^3)=832
2^3x*(1+4+8)=832
2^3x*13=832
2^3x=64
2^3x=2^6
3x=6
x=2