Step-by-step explanation:
<u>Step 1: Find the difference quotient</u>
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<em>Plug it into the formula</em>
<u>Difference Quotient:</u> 



<em>Pull out an h</em>
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Answer: 
Hi, this is the notation for inclusion of all real
numbers.

We can also state numbers which are positive or negative with a sign on top of the R notation like so:
I cant fully out my finger on it but I think it is both?
Answer:
-5
Step-by-step explanation:
9x +18=-27
9x = -27 -18
9x =-45
x = -45/9
x = -5
x= the number