2 (x + 4) is equivalent to 2x + 8 NOT 2 (x + 4) + 4
The first term is 138
The difference is 55
The iterative rule for the amount of money Mr Speas has after n weeks is
55/2 n² + 221/2 n
During the first week she has $138 in his bank account. At the end of each week she deposited $55 into her bank account.
The first term will be 138 .
The common difference is 55 because her bank always increase by $55 dollars every week. The sequence will be 138, 193, 248, 303, 358...…
The difference = 193 - 138 = 55.
The iterative rule for the amount of money Mr Speas has after n weeks can be represented below
n = number of weeks
a = first term = 138
d = common difference = 55
Using AP formula,
sₙ = n/2(2a + (n - 1)d)
sₙ = n/2 (2(138)+ (n - 1)55)
sₙ = n /2(276 + 55n -55)
sₙ = n /2(221 + 55n)
sₙ = 55/2 n² + 221/2 n
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D.8
A and C are out because they would get you ether lower or equal to 20, which is equal to AC and your trying to find X in AB which is so posed to be the what equals AC+BC.
AB=AC+BC
5x=20+BC
5(8)=20+BC
40=20+BC
40=20+20
AC equals 20. AB will have to equal AC+ CB. If you put in A.4 in AB 5X you will get twenty and that not what you want. You want to get a number that will get you the an answer greater to AC. So 5(8)=40.
Should we simplify or solve for m...?