Answer:
Savings on electricity per year by brand B = 114.3 - 104.76 = $9.54
Step-by-step explanation:
Ms. Wang is shopping for a new refrigerator. Brand A costs $569 and uses 635 kilowatt-hours per year. Brand B costs $647 and uses 582 kilowatt-hours per year.
Let's assume he buys brand B, so he already has a loss over the price of the commodity that is , loss = 647 - 569 =$78
Cost of electricity = $0.18
Now in the case of electricity,
spending on Brand A = 635
0.18 = $114.3
spending on Brand B = 582
0.18 = $104.76
Savings on electricity per year by brand B = 114.3 - 104.76 = $9.54

You would take 113.087335529 and divide by pi
Desmos graphing calculator will draw this graph for you.
draw 2 curves
y = x^4 + x^3
and
y = 4x^2 + 4x
The roots are the points where the 2 curves intersect.
You can see by simple substitution that one root is zero.
x^4 + x^3 - 4x^2 - 4x = 0
f(2) = 16 + 8 - 4(4) - 4(2) = 0 so 2 is another root
f(-2) = 16 - 8 - 16 + 8 = 0 so -2 is another root
f(-1) = 1 - 1 - 4 + 4 = 0 so -1 is the other root
The answer is A
You need to group the like terms (the terms with the same or no variable) together so it is:
5y-6y-y +6
Then you combine the like term and it becomes
5y-7y +6
-2y+6
which can also be written as 6-2y
Hope this helps :)