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C(8)=29 you have to plug in 8 for n in the equation and solve. Hope this helps!!!
Answer:920
Step-by-step explanation:
plug it in a calculator
Answer:

Step-by-step explanation:
Total number of toll-free area codes = 6
A complete number will be of the form:
800-abc-defg
Where abcdefg can be any 7 numbers from 0 to 9. This holds true for all the 6 area codes.
Finding the possible toll free numbers for one area code and multiplying that by 6 will give use the total number of toll free numbers for all 6 area codes.
Considering: 800-abc-defg
The first number "a" can take any digit from 0 to 9. So there are 10 possibilities for this place. Similarly, the second number can take any digit from 0 to 9, so there are 10 possibilities for this place as well and same goes for all the 7 numbers.
Since, there are 10 possibilities for each of the 7 places, according to the fundamental principle of counting, the total possible toll free numbers for one area code would be:
Possible toll free numbers for 1 area code = 10 x 10 x 10 x 10 x 10 x 10 x 10 = 
Since, there are 6 toll-free are codes in total, the total number of toll-free numbers for all 6 area codes = 
Let x be the digit in the tens place and y be the digit in the ones place.
so, the digit is xy
<span>
The ten's digit of a two digit number is 1 more than 4 times the units' digit.
</span>x = 4y + 1
<span>63 is subtracted from the number, the order of the digits is reversed
</span>10x + y - 63 = 10y + x
9x - 9y = 63
x = 4y + 1 ------------ (1)
9x - 9y = 63 ---------- (2)
Sub (1) into (2)
9(4y + 1) - 9y = 63
36y + 9 - 9y = 63
27y = 63 - 9
27y = 54
y = 2 ------- sub into (1)
x = 4(2) + 1 = 9
x = 9, y = 2
The number is 92