For what two values is this expression undefined?

Type your answer as two integers separated by a comma, like this: -4, 12

x^2+x−2/x^2+9x−10

Question

For what two values is this expression undefined?


Type your answer as two integers separated by a comma, like this: -4, 12

x^2+x−2/x^2+9x−10

mertsj · Answer

The two values that cause the denominator to be 0.

anonymous · Answer

so -2, -10

mertsj · Answer

no

mertsj · Answer

Solve this equation:
$$x^2+9x-10=0$$

anonymous · Answer

i am not sure. really am not good with math.

mertsj · Answer

Factor the left side.

anonymous · Answer

im not sure, i cant seem to find the numbers in the factor

mertsj · Answer

Think of two numbers:  If you multiply them you get -10
What could the numbers possibly be?

anonymous · Answer

-5,2 and -2,5

mertsj · Answer

Are there any other possibilities?

anonymous · Answer

-10,1 and -1,10

mertsj · Answer

So you have 4 possibilities.  Take each pair of numbers and add them together.  Is one answer 9?

anonymous · Answer

yes the -1 and 10

mertsj · Answer

typo.  the factors are x-1 and x+10

mertsj · Answer

In other words.  x^2+9x-10=(x-1)(x+10)

mertsj · Answer

So if you set the denominator equal to 0 you have:
$$x^2+9x-10=0$$
$$(x-1)(x+10)=0$$

mertsj · Answer

If the product of factors is 0, then at least one of the factors has to be 0.
Set each factor equal to 0 and solve the two equations.

anonymous · Answer

$$x-1=0$$
$$x=1$$
$$0$$

anonymous · Answer

right

mertsj · Answer

Yes.  1 is one of the numbers that will cause the denominator to be 0.
Find the other one.

anonymous · Answer

-10

anonymous · Answer

this is what I got from solving the factor

mertsj · Answer

Very good.

anonymous · Answer

so thats the answer

mertsj · Answer

There are two answers.  They are 1 and -10