4 12 18
:) fun little riddle
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 
--------------------------------------------------------------------------------------------------
To check this
When 



When 


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

Writing l as a function, we have:

Substitute
for l in 
becomes

First, we find the slope
(4,0)(0,-3)
slope = (-3 - 0) / (0 - 4) = -3/-4 = 3/4
there can be 3 possible answers for this..
y - y1 = m(x - x1)
slope(m) = 3/4
using points (4,0)...x1 = 4 and y1 = 0
now we sub
y - 0 = 3/4(x - 4) <== this is one answer
y - y1 = m(x - x1)
slope(m) = 3/4
using points (0,-3)...x1 = 0 and y1 = -3
now we sub
y - (-3) = 3/4(x - 0) =
y + 3 = 3/4(x - 0) <== here is another answer
y - y1 = m(x - x1)
slope(m) = 3/4
using points (-4,-6)...x1 = -4 and y1 = -6
now we sub
y - (-6) = 3/4(x - (-4) =
y + 6 = 3/4(x + 4) <=== and here is another answer