algebra ex.3 pg. 379

ex. 3,

Domain:

is the set of all real numbers that can be used in place of the variable.

The domain must exclude all of the numbers for which would cause the denominator to = to 0.

a) x2-9/x+3

with -3+3=0 determines that -3 can not be in the denominator.

the domain is the set of all real numbers that can be used in the place of a variable except -3. It is used in a set notation{x|xnot=-3}.

review the operations of adding and subtracting signed numbers.

b) x
____

x2 -x-6

1. figure out the domain and the number to exclude; then put it in a set notation.

2. the denominator needs to be factored.

x2 can be divided in to x2-x-6=0

(x-3)(x+2)=0 3.2=6 the 2 x's= x2 associative theory., distributive.

x-3=0 or x+2=0

x=3 or x= -2

review signs for multiplication;

review this problem again, as for as the - sign for the 3 and the -sign for the 2.

the set theory is as follows:

{x|xnot = to -2 and xnot=to 3} a negative 2 and a positive 3=0.

c). x-5
________
4

The denominator can not = to 0 since the d is 4. or -2, and 2=0

excercises from 21-28.

21. x2+x
_________
x-2

find the domain;

all real numbers except for +2.

23. -x
________

x2+5x+6

factor and use either associative or distributive.

(x+3)(x+2)

all real numbers except -3 -2.

25. x2-4
________
2

R because the denominator is 2

the denominator is the set of all real numbers.

27. x-5/x

all real numbers except 0.

that is all for now.

A Bacholor of Arts degree in Psychology will happen.
I am determined and have perserverance.