We can use the logarithmic identity log_a(b) + log_a(c) = log_a(bc) to simplify the left side of the equation:
log_2(x) + log_4(x+1) = log_2(x) + log_2((x+1)^(1/2))
Using the rule log_a(b^c) = c*log_a(b), we can simplify further:
log_2(x) + log_2((x+1)^(1/2)) = log_2(x(x+1)^(1/2))
Now we can rewrite the equation as:
log_2(x(x+1)^(1/2)) = 3
Using the rule log_a(b^c) = c*log_a(b), we can rewrite this as:
x(x+1)^(1/2) = 2^3
Squaring both sides, we get:
x^2 + x - 8 = 0
This is a quadratic equation that can be solved using the quadratic formula:
x = (-b ± sqrt(b^2 - 4ac)) / 2a
where a = 1, b = 1, and c = -8. Plugging in these values, we get:
x = (-1 ± sqrt(1^2 - 4(1)(-8))) / 2(1)
x = (-1 ± sqrt(33)) / 2
x ≈ -2.54 or x ≈ 3.54
However, we must check our solutions to make sure they are valid. Plugging in x = -2.54 to the original equation results in an invalid logarithm, so this solution is extraneous. Plugging in x = 3.54 yields:
log_2(3.54) + log_4(4.54) = 3
0.847 + 0.847 = 3
So x = 3.54 is the valid solution to the equation.