What is the domain of #f(x)= (x^2+18x+18 ) / ( x^2+9x+20)#?

1 Answer
Jacobi J.
Mar 19, 2018

#x inRR#

Explanation:

If we look at the numerator and denominator, they are both quadratics, which are defined and continuous for all real numbers.

Defined and continuous #<=># #x inRR#

We can plug in any value for #x# and get a value for #f(x)#. It doesn't matter that it's a fraction- even if #x# is zero, we get a value, #9/10#.

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