3^ (x+1) + 18/3^ (x) - 29=0

6*2^ (2x) - 13*6^ (x) + 6*3^ (2x) = 0

1) 3*3^2x-29*3^x+18=0

3^x=a

3a²-29a+18=0

D=841-216=625

a1 = (29-25) / 6=2/3⇒3^x=2/3⇒x=log (3) 2/3

a2 = (29+25) / 6=9⇒3^x=9⇒x=2

2) 6*2^ (2x) - 13*6^ (x) + 6*3^ (2x) = 0 / 3^2x

6 * (2/3) ^2x-13 * (2/3) ^x+6=0

(2/3) ^x=a

6a²-13a+6=0

D=169-144=25

a1 = (13-5) / 12=2/3⇒ (2/3) ^x=2/3⇒x=1

a2 = (13+5) / 12=3/2⇒ (2/3) ^x=3/2⇒x=-1