Question 187020
Find all the numbers for which each rational expression is undefined. If the rational expression is defined for all real numbers, so state. 
(y+8)/ 16y^2-y-2
Solve 16y^2-y-2 = 0
y = [1 +- sqrt(1 - 4*16*-2)]/32
y = [1 +- sqrt(129)]/32
y = [1 + sqrt(129)]/32 or y = [1 - sqrt(129)]/32
These are the values of y for which the expression is not defined.

------------------------------------------------------- 
page 457 Question 50
Divide as indicated.
(x^2+x)/(x^2-4) divided by (x^2-1)/(x^2+5x+6)
-----
Factor where you can to get:
[x(x+1) / (x+2)(x-2)] divided by [(x-1)(x+1)/(x+2)(x+3)]
---- 
Invert the denominator and multiply:
[x(x+1) / (x+2)(x-2)] multiplied by [(x+2)(x+3)/(x-1)(x+1))]
--------
Cancel any factors that are common to a numerator and a denominator
such as (x+1), (x+2)
[x / (x-2)] multiplied by [(x+3)/(x-1)]
-----------
Simplify:
[x(x+3)] / [(x-2)(x-1)]
===========================
Cheers,
Stan H.