trig
posted by jerson .
let f(x) =4x^46 evaluate f(3)

Raise 3 to the fourth power (giving you 81), multiply the result by 4, and subtract 6 from the result.
Surely you can do that on your own. 
you should be familiar with the terminology of this topic
if f(x) = 4x^4  6
f(3) = 4(3^4)  6
= 4(81)  6
= 3246
= 318 , (simply replace the x with 3 in the expression)
BTW, why did you label this question under the topic of "trig" ???