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Using solar energy, the total cost to heat a house includes an installation fee of $7,000 with an average cost of $280 per year.


using conventional fuel, the total cost to heat the same house includes an installation fee of $4,000 and an average cost of $580 per year
How many years until the total costs are the same for each?
A. 6
B.9
C10
D. 11

Respuesta :

chipp05

Answer:

C. 10 years

Step-by-step explanation:

For this question, we make an expression, and in that expression, our variable 'x' will represent however many years the house is using these forms of energy/fuel. S, our expression will look like this:

7000 + 280x = 4000 + 580x

Next, we subtract 4000 on both sides:

7000 + 280x = 4000 + 580x

-4000 -4000

3000 + 280x = 580x

Now, subtract 280x from both sides to isolate the variable:

3000 + 280x = 580x

-280x -280x

3000 = 300x

Finally, divide 300 on both sides to isolate the variable completely:

3000 = 300x

/300 /300

10 = x

or

x = 10

So, it will take C. 10 years until the total costs are the same for each

Hope this helps :)

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