SOLUTION: /------- Find the domain of f (x) = 7 + /3x + 21 , and express it using interval notation. a. [–7, ∞) b. [0, ∞) c. [7, ∞)

Algebra ->  Rational-functions -> SOLUTION: /------- Find the domain of f (x) = 7 + /3x + 21 , and express it using interval notation. a. [–7, ∞) b. [0, ∞) c. [7, ∞)       Log On


   

Question 107758: /-------
Find the domain of f (x) = 7 + /3x + 21 , and express it using interval
notation.
a. [–7, ∞)
b. [0, ∞)
c. [7, ∞)
d. [21, ∞)
Answer by Nate(3500) About Me  (Show Source):
You can put this solution on YOUR website!
f(x) = 7 + sqrt(3x + 21)
You can not take the square root of a negative value and receive a real value in return. So:
3x + 21 >= 0
3x >= -21
x >= -7
A