We use the formula a^2 - b^2 = ( a - b )( a + b );
We have a = 5m - 2 and b = 3m - 4;
<span>(5m-2)^2-(3m-4)^2 = (5m - 2 -3m + 4) x (5m-2 + 3m - 4) = (2m + 2)(8m - 6) = 2(m +1) x 2(4m - 3) = 4(m+1)(4m-3);
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Answer:
$25.00
Step-by-step explanation:
You already know that $85 is an additional fee added to the monthly fees.
So, you first have to subtract 85 from $685 to get the total amount of monthly fees paid over 2 years.
685-85= 600
So, you can conclude that $600 is the total amount of monthly fees paid.
Now, you want to divide 600 by (the number of months in 2 years) to get the amount of monthly fees.
Since there is 24 months in 2 years you do:
600/ 24 which equals 25. 
In conclusion, you can find that the monthly fee is $25.00.