SOLUTION: I don't get how to solve funtions. I get lost quickly. Any help out there? Given f(x)=5x^2/x-2 Evaluate f(-1) Evaluate f(3) State the domain of function f(x) thanks!

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Question 64444: I don't get how to solve funtions. I get lost quickly. Any help out there?
Given f(x)=5x^2/x-2

Evaluate f(-1)
Evaluate f(3)
State the domain of function f(x)
thanks!
Found 2 solutions by stanbon, josmiceli:
Answer by stanbon(75887) (Show Source):
You can put this solution on YOUR website!
Given f(x)=5x^2/(x-2)
Evaluate f(-1)=4(-1)^2/(-1-2)=4*1/(-3)=-(4/3)
Evaluate f(3)=5(3)^2/(3-2)=5*9/1=45
State the domain of function f(x)
When finding a domain it is easier to determine vales x CANNOT take.
In your function x CNNOT be 2 because that would make the denominator zero,
which would make the fraction meaningless.
That is the only value x CANNOT take.
So, the domain is all real number EXCEPT x=2.
Cheers,
Stan H.

Answer by josmiceli(19441) (Show Source):
You can put this solution on YOUR website!

f(-1) = ?
Just substitute -1 for x everywhere you see x in the function

f(3) = ?

If you do the long division, you get

As x grows positively, the 1st term gets more positive and the last term approaches zero.
As x grows negatively, the 1st term gets more negative, and the last term
still approaches zero.
When x = +2, the last term becomes +infinity.
So, the domain of this is +2 < x < +2