SOLUTION: What is the domain of State the domain of the following: a)f(x)= the square root of x-8 Answer: b)h(x)=3x squared + 5x-3 Answer: c)mx=5/x squared +9 Answer:

Algebra ->  Functions -> SOLUTION: What is the domain of State the domain of the following: a)f(x)= the square root of x-8 Answer: b)h(x)=3x squared + 5x-3 Answer: c)mx=5/x squared +9 Answer:       Log On


   

Question 110300: What is the domain of State the domain of the following:
a)f(x)= the square root of x-8
Answer:
b)h(x)=3x squared + 5x-3
Answer:
c)mx=5/x squared +9
Answer:
d)l(x)=5x-4

Answer by wgunther(43) About Me  (Show Source):
You can put this solution on YOUR website!
The domain is all values the function can take. There are two big things you can't do. You can't divide by 0 and you can't take even roots of negative numbers.
a) f%28x%29=sqrt%28x-8%29 So, x >=8 because if x<8 then x-8<0. So I'm not sure what notion you're using by it could be [8,inf) in interval notion or in set-builder notion {x|x=>8}
b) h%28x%29=3x%5E2+%2B+5x+-+3 h can take any input, so your domain is the real numbers.
c) m%28x%29=5%2F%28x%5E2%2B9%29 Here, the bottom can never be 0 because x%5E2%2B9%3E0, so the domain is once again all real numbers.
d) l%28x%29=5x-4 Once again, the domain is the real numbers. In b) and d) you have polynomial expressions which are always definied on the real numbers.