What will be the answer for this

3^(x+2) + 3^(-x) = 10
3^(x) *  3^2 + 1/3^x = 10
let 3^x be y
thus
9y + 1/y  = 10
9y^2 +1 = 10y
9y^2 -10y + 1 = 0
9y^2 -9y -y +1 = 0
(9y -1)(y -1 ) = 0
thus y  = 1/9 or 1
3^x   = 1/9 or 1
thus x = -2 or 0