SOLUTION: y-4/y^2-y-20 A) 0 and -5 B)0 and 5 C) 4 and -5 D) -4 and 5

Algebra ->  Test -> SOLUTION: y-4/y^2-y-20 A) 0 and -5 B)0 and 5 C) 4 and -5 D) -4 and 5      Log On


   

Question 1006489: y-4/y^2-y-20
A) 0 and -5 B)0 and 5 C) 4 and -5 D) -4 and 5
Answer by ikleyn(52776) About Me  (Show Source):
You can put this solution on YOUR website!
.
What is your question?

----------------------------------------------------------
Comment from student: Find the value of x that must be excluded in the algebraic fraction: y-4/y^2-y-20 — Thanks
----------------------------------------------------------

OK.

Let us consider the denominator of this function which is a quadratic polynomial p(x) = y%5E2-y-20.

It can be factored as p(y) = (y-5)*(y+4).

It has the roots y = 5 and y = -4.

Hence, the domain of the given rational function is the entire number line except two points y = 5 and y = -4, where the function is not defined.