SOLUTION: find (f-g)(x). What is the domain of f/g f(x)=2x-5 g(x)=2-x

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Question 147184: find (f-g)(x). What is the domain of f/g
f(x)=2x-5 g(x)=2-x

Answer by jim_thompson5910(35256)   (Show Source): You can put this solution on YOUR website!
Start with the given property


Plug in and


Distribute.


Combine like terms









Start with the given property


Plug in and


Set the denominator equal to zero. Remember, dividing by 0 is undefined. So if we find values of x that make the denominator zero, then we must exclude them from the domain.



Subtract 2 from both sides


Combine like terms on the right side


Divide both sides by -1 to isolate x



Divide





Since makes the denominator equal to zero, this means we must exclude from our domain

So our domain is:

which in plain English reads: x is the set of all real numbers except

So our domain looks like this in interval notation


note: remember, the parenthesis excludes 2 from the domain

If we wanted to graph the domain on a number line, we would get:

Graph of the domain in blue and the excluded value represented by open circle

Notice we have a continuous line until we get to the hole at (which is represented by the open circle).
This graphically represents our domain in which x can be any number except x cannot equal 2

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