SOLUTION: What is the domain of the following quadratic function? f(x)=2x^2+5x-7?

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Question 708131: What is the domain of the following quadratic function?
f(x)=2x^2+5x-7?
Answer by KMST(5328) About Me  (Show Source):
You can put this solution on YOUR website!
If no restrictions are stated, function f%28x%29 exists for all values of x that let you calculate f%28x%29.
A polynomial, like f%28x%29=2x%5E2%2B5x-7 can be calculated for any x,
so its domain is all the real numbers.
If you have to write "all the real numbers" in symbols,
you need to know how your teacher prefers to write that.
It could be (-infinity, infinity),
but there are different ways to state the same thing.

NOTE 1:
Some functions have a domain that excludes some numbers.
For example g%28x%29=sqrt%28x%29 does not exist for any negative x
and h%28x%29=1%2Fx does not exist for x=0.

NOTE 2:
Just as the highlight%28domain%29 of f%28x%29 is the set of all possible x values,
the highlight%28range%29 of f%28x%29 is the set of all possible f%28x%29 values.
The range of f%28x%29=2x%5E2%2B5x-7=2%28x-5%2F4%2962-81%2F8 only includes values such that
f%28x%29%3E=-81%2F8