SOLUTION: pg. 432, find the domain for each of the following funcions. 23. y= x +4 divided by x squared minus 4x i dont even know where to begin, or what to look for... teac

Algebra ->  Functions -> SOLUTION: pg. 432, find the domain for each of the following funcions. 23. y= x +4 divided by x squared minus 4x i dont even know where to begin, or what to look for... teac      Log On


   

Question 42114: pg. 432,
find the domain for each of the following funcions.
23. y= x +4 divided by x squared minus 4x
i dont even know where to begin, or what to look for...


teacher: rapalje
Answer by psbhowmick(878) About Me  (Show Source):
You can put this solution on YOUR website!
y+=+%28x+%2B4%29%2F%28x%5E2-4x%29
or y+=+%28x%2B4%29%2F%28x%28x-4%29%29

Division of a number by zero is not defined.
So, for y to be defined the denominator on the right side must not be 0 i.e. x(x - 4) must not be 0.
So neither x nor (x-4) can be zero.
So x can neither be 0 nor be 4.
This means that y is not-defined for x = 0 and x = 4.
So y is defined for all other values of x.
Hence, the domain is (-infinity,0), (0,4) and (4,infinity).

For a more detailed discussion and the use of brackets in designation of domains refer to my lesson at

http://www.algebra.com/tutors/FUNCTIONS.lesson?content_action=show_dev