How do I solve for x in 3^(2x+2)+8*3^(x)-1=0 ?

1 Answer
Mar 30, 2018

x = -2

Explanation:

3^(2x+2)+8xx3^(x)-1=0
3^(2x) xx 3^2 +8xx3^(x)-1=0
(3^ x)^2 xx 9 +8xx3^(x)-1=0

Let 3^x = a
9a^2 + 8a - 1 = 0
(a + 1)(9a - 1) = 0
a = -1, 1/9

3^x = a =>

3^x = -1: no solution

3^x =1/9
3^x = 3^(-2)
x = -2