How do you find the domain of #f(x)=(-3x^2)/(x^2+4x-45)#?

1 Answer
Aug 5, 2016

Answer:

Domain: all Real values except #(-9)# and #(+5)#

Explanation:

#f(x)=(-3x^2)/(x^2+4x-45)#
#color(white)("XXX")#will be defined for all Real values of #x#
#color(white)("XXX")#except those values which cause the denominator to be equal to zero.

That is the Domain will be all #RR#
except when
#color(white)("XXX")x^2+4x-45=0#

Factoring:
#color(white)("XXX")(x+9)(x-5)=0#

So the Domain of #f(x)# is
#color(white)("XXX")RR-{-9,+5}#