Question

$3^{x+2} + 3^{x-2} = 246$

Answer 1

$3^{x+2}+3^{x-2}=246\\ 3^2\cdot 3^x+ \frac{1}{3^2}\cdot 3^x=246|\cdot 9 \\ 81\cdot 3^x+3^x=246\cdot 9 \\ 82\cdot 3^x=246\cdot 9 \\ 3^x=3\cdot 9 \\ 3^x=3^3 \\ x=3$

Answer 2

3^(x-2)*(81+1)=246
3^(x-2)*82=246
3^(x-2)=246:82=3
x-2=1
x=1+2=3