Question 1041087: Hi, I'm having trouble figuring out this question:
Determine which of the value(s) given below, if any, must be excluded from the domain of the variable in each expression.
(a) x=3 (b) x=1 (c) x=0 (d) x=-1
1.) x^2 - 1 / x
2.) x / x^2 - 9
3.) x^2 / x^2 + 1
4.) x^2 + 5x - 10 / x^3 - x
Thank you.
Answer by Boreal(15235)   (Show Source):
You can put this solution on YOUR website! for the first, x cannot be 0.(c)
2. x^2-9 cannot be 0, so it is 3 and -3. (a is best choice)
3.x^2+1 cannot be 0. No real number is excluded from the domain.
4. x^3-x cannot be 0, so x(x^2-1) cannot, and 0, 1, and -1 cannot be (b,c,d)
Set the denominator equal to 0 and solve. Whatever the roots are cannot be part of the domain, for one will be dividing by 0.
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