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What makes this undefined.

What makes this undefined.-example-1
User Diedra
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2 Answers

7 votes

Answer: The expression is undefined when x is 3 or -3

Explanation:

The denominator of a fraction can never be 0 because you cannot divide by 0. So all we have to do is determine the value of x when the denominator is equal to 0.


9-x^(2) =0\\

We want
x^2 to be positive so divide everything by -1


9-x^(2) =0\\\\(9-x^(2))/(-1)=(0)/(-1) \\-9+x^2=0\\x^2-9=0

Use difference of two squares (DOTS) to factor


x^2+9=0\\(x+3)(x-3)=0

So x cannot be 3 or -3

User Ron Diel
by
7.2k points
0 votes

Answer:

The expression is undefined when x=3 or -3

Solution:

  • An expression is undefined when it's divided by 0.
  • In order to make the denominator equal 0, we need to subtract 9-9.
  • Notice that x is squared.
  • So x times itself should equal 9. What number is it?
  • That's right, 3.
  • So we have
  • 9-(3)^2=9-9=0
  • There's also another solution: x=-3 (-3•(-3)=9

Hope it helps.

Do comment if you have any query.

User Xophmeister
by
7.9k points

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