# Questions on Algebra: Sequences of numbers, series and how to sum them answered by real tutors!

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 Question 749911: Write the following as a summation and find the sum of the series (3-1)+(1/3-1/9)+.... Click here to see answer by reviewermath(721)

 Question 750086: I have a question which goes like this: An = 2-A*n-1, where A5 = 3. I need to find the tenth value. The answer is -1 but I don't know exactly how to do it. Can you please help me out? Thank you Click here to see answer by rothauserc(643)

 Question 750465: Find the fractions equal to the given decimals 1. 0.70707 Click here to see answer by tommyt3rd(3721)

 Question 750549: Starting with n=1, find the first 5 terms of: . Please explain the steps the best that you can. Thanks. :) Click here to see answer by MathLover1(7480)

 Question 750669: how many terms are needed to make the sum of 4+17/4+9/2+... first exceed 80? Click here to see answer by MathLover1(7480)

 Question 750752: Find the 24th term of the arithmetic sequence whose common difference is 2 and whose first term is 4. Click here to see answer by timvanswearingen(106)

 Question 751099: find the 9th term of a geometric progression whose 4th and 7th terhs are -4 and 256 respectively Click here to see answer by stanbon(60778)

 Question 751294: Find the seventh term of the geometric sequence 1,1/5,1/25 Click here to see answer by reviewermath(721)

 Question 751306: The product of two consecutive integers is 9 less than 9 times their sum. Find the integers. I would like to know how to do this problem Click here to see answer by stanbon(60778)

 Question 751318: The area of a square is numerically 77 more than the perimeter. Find the length of the side Click here to see answer by reviewermath(721)

 Question 751451: Please help me, solve the given problems involving factorials Show that ( n+ 1) ! ------ = n ^3 - n for n ≥ 2 (n - 2) ! Click here to see answer by reviewermath(721)

 Question 751737: A side of an equilateral triangle is 10 cm. the midpoints of its sides are joined to form an inscribed equilateral triangle, and this process is continued. Find the sum of the perimeters of the triangles if the process is continued without end. Click here to see answer by reviewermath(721)

 Question 752003: For questions 3-5, find the first 4 terms and the 8th term of the recursively-defined sequence. 3. b1 = 2 and bk+1 = 3bk, for k>0 4. v1 = 0.75 and vn = (-2)vk-1 for n>1 5. c1 = 2, c2 = -1, and ck+2 = ck + ck+1 for k>0 Click here to see answer by stanbon(60778)

 Question 752134: I don't recall viewing any similar problems during the series and sequences unit this year, so any help would be appreciated. How many license plates can be made if they are formed by 3 letters, followed by 3 digits, followed by a letter? Digits and letters may be repeated. Click here to see answer by josmiceli(10616)

 Question 752230: Given the first term, a1, the common difference, d , and the arithmetic sequence a1 = 6, d = 8, the 20 th term would be? Click here to see answer by stanbon(60778)

 Question 752300: Write the first four terms of the geometric sequence satisfying the following conditions: a2 = 11, and a3 = -121 Click here to see answer by reviewermath(721)

 Question 752362: Find the sum of the first 5 terms of the sequence defined by an = -7(-4)n − 1 for n ≥ 1. Click here to see answer by stanbon(60778)

 Question 752568: the number of positive integers whose square is a factor of 2000 is out of A) 3 B) 6 C)10 D) 12 E)20 Thank you for your help! I really don't have a clue how to do this, neither do my friends. And we all don't know WHAT intergers are. Thanks!! Click here to see answer by Edwin McCravy(9719)

 Question 752570: A hardware store sells numerals for house number. It has large quantities of the numerals 3, 5, and 8 but no other numerals. How many different house numbers, with no more than 3 digits, can be made form those numerals? A) 33 B)21 C)27 D)36 E)39 Thanks! Well, so far I've worked out that you could have A =3 B= 5 and C=8, and then go a, aa, aaa, ab,abb,aab,ac,acc, aac, but I always get confused even when I write it down. Thanks for bothering to help me! Click here to see answer by JoeTaxpayer(186)

 Question 752588: when 200 is divided by a positive integer N, the remainder is 5. the number of all possible values of N is: A) 2 B)6 C)8 D)13 E)16 Thank you very much for looking at this question. I have worked out that N - 40, but I'm not sure how to continue on from there. Click here to see answer by Edwin McCravy(9719)

 Question 752677: in the minimum value in a series 40 and its range is 67, then find the maximum value of the series. Click here to see answer by tommyt3rd(3721)

 Question 753041: Consider the arithmetic sequence that begins with the numbers 15 and 21. What is the 10th number in this sequence? Click here to see answer by reviewermath(721)

 Question 753039: Find the first 4 terms of the following recursive sequence, an = an−1 − 10 , a1 = 20 Click here to see answer by tommyt3rd(3721)

 Question 753244: 1; 8; 27; 64; does this number have a common difference? Click here to see answer by josgarithmetic(3317)

 Question 725048: In a geometric mean, if 5th term is 32 and 8th term is 84. Find geometric mean Click here to see answer by tommyt3rd(3721)

 Question 753628: Describe the rule for the sequence: -5, 7, 19, 31, ... Click here to see answer by solver91311(18785)

 Question 753668: For questions 1–6 determine whether each series is arithmetic or geometric. Then evaluate the series to the given term. 1. 1 + 3 + 9 + ...; S8 2. 5 + 7 + 9 + ...; S8 3. 25 + 32 + 39 + ...; S12 4. 256 + 192 + 144 + ...; S7 5. 1 – 3 + 9 – 27 + ...; S10 6. -14+(-7)+ 0 + 7 + ...; S10 I really appreciate all of the help I can get! :) Click here to see answer by solver91311(18785)

 Question 753751: ?Rafael drove 260 miles using 11 gallons of gas. At this rate, how many gallons of gas would he need to drive 390 miles Click here to see answer by MathLover1(7480)

 Question 753616: Write a rule for the nth term of the arithmetic sequence, then find a23 d=-2/3,a4=18 Click here to see answer by KMST(2478)

 Question 753895: If a 117-mile trip took 6 1/2 gallons of gas, how many miles can be driven with a full tank of 20 gallons? Click here to see answer by josmiceli(10616)

 Question 754041: x+3, x-15, 24 are the first 3 terms to a geometric sequence, find the values of x. Click here to see answer by reviewermath(721)

 Question 754255: Viola makes gift baskets for Valentine's Day. She has 13 baskets left over from last year, and she plans to make 12 more each day. If there are 15 work days until the day she begins to sell the baskets, how many baskets will whe have to sell? Click here to see answer by stanbon(60778)

 Question 754252: Write a recursive formula for the sequence 15,26,48,92,180,.......Then find the next term. Click here to see answer by stanbon(60778)