Answer:
(a) 
(b) Domain:
<em>(See attachment for graph)</em>
(c) 
Step-by-step explanation:
Given



Solving (a): A function; l in terms of w
All we need to do is make l the subject in 
Divide through by 2

Subtract w from both sides


Reorder

Solving (b): The graph
In (a), we have:

Since l and w are the dimensions of the fence, they can't be less than 1
So, the domain of the function can be 
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To check this
When 



When 


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<em>See attachment for graph</em>
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Solving (c): Write l as a function 
In (a), we have:

Writing l as a function, we have:

Substitute
for l in 
becomes

I have the best ans and that is
<h2>y + 1 = -3(x - 10)</h2>
Here's the formula:
y - y1 = m(x - x1)
Substitute numbers accordingly:
y1: so 1 goes in the y1 spot (you switch the signs because it was already negative)
x1: and 10 goes to the x1 spot
m: -3 belongs in m
There are no values for x that make the equation true