1. ## Need some help

Hi yall im new to this forum but im looking for some help.

Find all values of the variable for which the expression is undefined.

1) (4y)/( x- 3)
2) (4x + 12)/ (x^3 - 9x)
3) (7)/ (7 -x )
4) (2y)/ (y^2 - 6y - 7)
5) (7)/ (x^2 -4)
6)(4x)/ (2x - 1)

2. Originally Posted by xfactor0707
Hi yall im new to this forum but im looking for some help.

Find all values of the variable for which the expression is undefined.

1) 4y/ x- 3 2) 4x + 12/ x^3 - 9x 3) 7/ 7 -x 4) 2y/ y^2 - 6y - 7

5) 7/ x^2 -4 6) 4x/ 2x - 1

what you wrote is confusing. clarify

start by writing each new question is a new line

then be sure to type fractions as follows: (numerator)/(denominator)

that is, to type $\displaystyle \frac {x + 7}{x^2 + 1}$ type (x + 7)/(x^2 + 1)

3. Originally Posted by xfactor0707
Hi yall im new to this forum but im looking for some help.

Find all values of the variable for which the expression is undefined.

1) (4y)/( x- 3)
2) (4x + 12)/ (x^3 - 9x)
3) (7)/ (7 -x )
4) (2y)/ (y^2 - 6y - 7)
5) (7)/ (x^2 -4)
6)(4x)/ (2x - 1)

Much better!

We are looking for values of x where the expression is undefined. In the case of fractions we look for where the denominator is 0.

So for 1)
$\displaystyle \frac{4y}{x- 3}$
we know that $\displaystyle x - 3 = 0$ is forbidden. Thus x = 3 is where the expression is undefined.

A more complicated example is number 4)
$\displaystyle \frac{2y}{y^2 - 6y - 7}$

We are looking for places where
$\displaystyle y^2 - 6y - 7 = 0$

$\displaystyle (y - 7)(y + 1)= 0$

So y cannot be -1 or 7.

See what you can do with the rest.

-Dan