ch.6 ex. problems 21-28 pg. 386

Find the domain of each rational expression:

The domain in an algebraic expression is a set of numbers that can be put in the place of a variable. For rational expressions, the domain must exclude any real numbers that cause the denominator to be 0.

21. x2+X
_______=+2

x-2

all real numbers except 2.

23. x
________

x2+5x+6

all real numbers except -3 and -2.

use factorization with distributive and associative properties;

is 0 if; (x+2)(x+3)=0. or

x+2=0 OR x+3=0

The set of domain is the set of all real numbers except -3, and -2.

25. x2-4
________= R

2

The answer is R because the denominator is 2.

27. x-5
____= all real numbers except 0.

That is all for now.

Marie Zajac
Bachelor of Arts degree in Psychology

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