Question

Consider the function f(t) = 3t-9 . You cannot take the square root of a negative number, so 3t – 9 must be____ zero.

Answer 1

I think you mean
$f(t)=\sqrt{3t-9}$

so therefor since we can't take squaer root of negative

3t-9 must not be negative
basicaly, 3t-9 must be greater than or equal to 0

Answer 2

Greater than or equal to

I hope this helps, and God bless <3