How do you find the domain of f(x) = sqrt(7x + 2)?

1 Answer
Oct 7, 2016

Domain: {x|x>=-2/7} or Domain:[-2/7,oo)

Explanation:

We know that the we cannot find a real solution to the sqrt of a negative number. This lets me know that 7x+2>=0.

Solve:

7x+2>=0

7x>=-2 (Subtract 2 from both sides.)

x>=-2/7 (Divide both sides by 7.)

This tells us that we can only use x's>=-2/7 in our domain.

Domain: {x|x>=-2/7} or Domain:[-2/7,oo)