Solve and find the domain of the equation:
\(\log _3 (4 \cdot 3^{x-1}-1)=2x-1\)
log3 (4*3x- 1 - 1) = 2x - 1 write this in exponential form
3^(2x - 1) = 4*3^(x - 1) - 1
3^(2x) / 3 = 4*3^x / 3 - 3/3 multiply through by 3
3^(2x) = 4*3^x - 3
(3^2)^x = 4*3^x - 3
(3^x)^2 = 4*(3^x) - 3
Let a = 3^x
a^2 = 4a - 3
a^2 - 4a + 3 = 0 factor
(a - 3) (a - 1) = 0
Set each factor to 0 and solve for a and we get that
a = 3 or a =1 which means that
1 = 3^x ⇒ x = 0 or that
3 = 3^x ⇒ x = 1
Both solutions solve the original equation
I'm sorry...but I don'tknow what "domain of the equation" means....unless we require that
4*3^(x - 1) - 1 > 0 if so.....then
4*3^(x - 1) . 1
3^(x - 1) > 1/4 take the log of both sides
(x - 1) log(3) > log (1/4)
log (3) * (x) > log (1/4) + log (3)
x > [ log (1/4) + log (3) ] / log (3)
x > log (3/4) / log(3)
x > ≈ -0.262 ⇒ this is the domain