SOLUTION: Evaluate the function. given that f(x) = sqrt -9x , find f(-k). A) sqrt kx B) sqrt 9k C) sqrt -9k D) sqrt -kx

Algebra ->  Equations -> SOLUTION: Evaluate the function. given that f(x) = sqrt -9x , find f(-k). A) sqrt kx B) sqrt 9k C) sqrt -9k D) sqrt -kx       Log On


   

Question 201558: Evaluate the function.
given that f(x) = sqrt -9x , find f(-k).
A) sqrt kx
B) sqrt 9k
C) sqrt -9k
D) sqrt -kx
Answer by jsmallt9(3758) About Me  (Show Source):
You can put this solution on YOUR website!
In general, if you know f(x) then to find f(anything) you
  1. replace all instances of x in f(x) with anything surrounded by parentheses
  2. simplfy


For your f%28x%29+=+sqrt%28-9x%29
f%28y%29+=+sqrt%28-9%28y%29%29+=+sqrt%28-9y%29
f%28-2%29+=+sqrt%28-9%28-2%29%29+=+sqrt%2818%29
f%28x%2B1%29+=+sqrt%28-9%28x%2B1%29%29+=+sqrt%28-9x%2B+%28-9%29%29
f%283x%2By%29+=+sqrt%28-9%283x%2By%29%29+=+sqrt%28-27x%2B+%28-9y%29%29
and last but not least:
f%28-k%29+=+sqrt%28-9%28-k%29%29+=+sqrt%289k%29