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

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Answer 1 · 2016-10-07T14:19:15

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

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)#