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 Thread: Algebra 2 help? View Single Post 07-26-2007 #5 Lain Lain Guest   Posts: n/a First of all, are you not gonna try any of those problems yourself at all? Anyway ...1). Doesn't it seems like it's increasing by 5?2). 1/(3^3) + 1/(3^4) + 1/(3^5) + 1/(3^6) and it's a geometric series and r = 1/3. You should be able to solve it by simply plug in the values in geometric series equation.3). Tn+2 = 3tn / 2tnT3 = T1+2 and so, n =1.T3 = 3(t1) / 2(t1) = 3(-2) / 2(-2) = 3/2.By the way, are you sure the problem is Tn+2 = 3tn / 2tn? it will gives you 3/2 for every term because tn cancels each other.4). I don't know what you mean5). I don't know what you mean6). T1 = 20 - 9(1) = 11T2 = 20 - 9(2) = 2T3 = 20 - 9(3) = -7So, your d = -9 in the arithematic sequence equation. To find the rest of the six terms, you can use arithematic sequence formula or just continue using Tn = 20 - 9n.7). Arithmetic sequence formula saysan=a1+(n-1)d, so plug in last term is an=-3, first term a1= 5, there are three terms in between, so that makes n = 5-3=5+(5-1)d -3=5+4d-8=4dd=-2start with 5 and then adding -2 to 5 gives 3, and adding -2 to 3 gives 1, and adding -2 to 1 gives -1. So, your answer is 3, 1 and -1.8). Look at my answer for 7 and you should try it yourself.9). Well, you start out with 20, so your a1 = 20, your d = 1 since each row has one additional seat. So, it's gonna be,20 + 21 + 22 + ... + 69The last row is going to be 20 + 49. So, an = 69. Now you have all the term and you should be able to figure out how to use the arithematic series formula.10). -5, -13, -21, .... and looks like it's adding -8. So, your a1 = -5, and your d = -8. You can continue from now. 