SOLUTION: What values of x may not be used in the expression ((x+5)/(x^2-4))? I am completely clueless on this stuff it confuses me! Thanks

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Question 133681: What values of x may not be used in the expression ((x+5)/(x^2-4))?
I am completely clueless on this stuff it confuses me!
Thanks
Found 2 solutions by scott8148, jim_thompson5910:
Answer by scott8148(6628) About Me  (Show Source):
You can put this solution on YOUR website!
usually, the reason a value may not be used is that it would result in an undefined operation
__ like division by zero

values of x that make x^2-4 equal zero are no-no's

x^2-4=0 __ factoring __ (x+2)(x-2)=0 __ so x+2=0 and x-2=0

so x can't be 2 or -2

Answer by jim_thompson5910(35256) About Me  (Show Source):
You can put this solution on YOUR website!

f%28x%29=%28x%2B5%29%2F%28x%5E2-4%29 Start with the given function


x%5E2-4=0 Set the denominator equal to zero. Remember, dividing by 0 is undefined. So if we find values of x that make the denominator zero, then we must exclude them from the domain.




%28x-2%29%28x%2B2%29=0 Factor the left side (note: if you need help with factoring, check out this solver)




Now set each factor equal to zero:

x-2=0 or x%2B2=0

x=2 or x=-2 Now solve for x in each case


So our solutions are x=2 or x=-2



Since x=-2 and x=2 make the denominator equal to zero, this means we must exclude x=-2 and x=2 from our domain