Question

Please help me with this question!!!!!! PLEASE.

Answer 1

B. -9, 7

Explanation:

For the rational expression to be undefined the denominator has to equal 0.

x² + 2x - 63 = 0

Factor left side.

(x - 7)(x + 9) = 0

Set factors equal to 0.

x - 7 = 0

x = 7

x + 9 = 0

x = -9

x = -9 or x = 7

Answer 2

B

Explanation:

A rational expression is undefined when the denominator of the expression equals 0 (this is because anything over 0 is undefined). In other words, to find the values for which the given expression is undefined, we simply have to find the zeros of the denominator. We can ignore the numerator. Thus, let:

`0=x^2+2x-63`

This is now a quadratic. Solve for the quadratic. I will factor but you can do whatever you like (complete the square, quadratic formula, etc.).

We notice that two factors that multiply to -63 and also add to +2 is 9 and -7. Thus:

`0=(x+9)(x-7)`

`x+9=0 ; x=-9`

`x-7=0; x=7`

The zeros are -9 and 7.

The denominator will equal 0 at these values, and the expression will be undefined.