What is the smallest real number x in the domain of the function g(x) = sqrt((x - 3)^2 - (x - 18)^2)?
The number x is in the domain when (x - 3)^2 - (x - 18)^2 is non negative.
(x - 3)^2 - (x - 18)^2 >= 0
(x^2 - 6x + 9) - (x^2 - 36x + 324) >= 0
30x - 315 >= 0
30x >= 315
x >= 10.5
=^._.^=
