Question 1041088
I'll do problem 1 to get you started. 


I'm assuming the entire denominator is x-5. If so, then set the denominator equal to 0 and solve for x


x-5 = 0
x-5+5 = 0+5
x+0 = 5
x = 5


So if x = 5, then the denominator x-5 is equal to 0


Recall that you cannot divide by zero. So we must exclude x = 5 from the denominator to avoid division by zero errors. 


Therefore, the domain is the set of all real numbers BUT x cannot equal 5. You can pick any other number you want for x.