Your answer should be, BTU / cubic foot = 650 (4) (4) / 5000 = 2.08 BTU / ft^3, Hope this helps you! :D
For this case, the first thing we must do is define a variable.
We have then:
x: number of weeks
y: amount of cereal that Melanie eats
We now write the function that models the problem:

Then, for 5 weeks we have:
Answer:
A model that best represents the number of pounds of cereal she eats is:
For 5 weeks we have:
I think the answer is 2( 4x+3)(x-2)
X-4y=-12
4x-y=12
eliminate y's
multily 2nd equaiton by -4 and add to top one
x-4y=-12
<u>-16x+4y=-48 +
</u>-15x+0y=-60
-15x=-60
divide both sides by -15
x=4
sub back
x-4y=-12
4-4y=-12
minus 4 both sides
-4y=-16
divide both sides by -4
y=4
x=4
y=4
(x,y)
(4,4)<u>
</u>