find the domain of k^2-k-20 ,does it have excluded values in the domain if yes, explain

Question

Write the domain of each rational expression in set notation. k^2-k-20/18 and 6b-3/3b^2-12.  Do both rational expressions have excluded values in their domains? if yes, explain why they are to be excluded from the domains. if no, explain why no exclusions are necessary, and Incorporate the following math vocabulary:

domain, excluded balue, set, factor, real numbers

 

Answer 1

y=x^2-x-20=(x+4)*(x-5)

good for all reel x