What is the domain of the function

Answer:
The domain of the function is x>=-7
Step-by-step explanation:
The domain is all the values that x can take so the function is defined, that means we can find a value of y
The sqrt is defined only for positive values and zero. So the expression in the sqrt must satisfy that
6x + 42 >=0
We only have to find x
6x >=-42
x>=-42/6
x>=-7
So the answer is D x>=-7