How do find the x-intercept of f(x)=2log4(x)?

1 Answer
Sep 29, 2015

(1/4, 0)

Explanation:

The x-intercept occurs where the graph intercepts the x-axis - in other words, where f(x) = 0. So, all we have to do is set f(x) equal to 0 and solve for x. Let's do it:

0 = 2log4x (setting f(x) equal to 0)
0 = log4x (dividing by 2)
10^0 = 10^(log4x) (10 to the power of both sides, to cancel out logarithm)
1 = 4x (simplifying; 10^0 = 1, 10^(log4x) = 4x)
x = 1/4 (dividing by 4 to isolate x)

Thus, the x-intercept of f(x) = 2log4x occurs at the point (1/4, 0).