Wednesday

October 22, 2014

October 22, 2014

Posted by **Rebekah** on Sunday, May 12, 2013 at 5:31pm.

a)the 8th term is 8 and the 20th term is 44

b) the 8th term is 4 and the 18th term is -96

thanks!! I am just confused how you do this if you dont know what n is.

- Precalc -
**Steve**, Monday, May 13, 2013 at 12:04amI assume these are arithmetic sequences, so

a)

Tn = a+(n-1)d so

a+7d = 8

a+19d = 44

12d = 36, so d=3

a = -13

or, you can do it like this.

T20-T8 = 12d = 44-8 = 36, so d=3

similarly, for

b)

10d = -100

d = -10

a = 74

**Answer this Question**

**Related Questions**

Math - The nth term of an A.P. Is 3 times the 5th term.(a)find the relationship ...

Maths - 1) In the arithmetic progression, the 8th term is twice the 4th term and...

Maths - The 3rd term of an AP is 10 more than the first term while the fifth ...

math - The 8th term of ap is 5time the 3rd term, while the 7th term is greater ...

arithmetic - The 8th term of an A P is 5times the third term while the 7th term ...

Math - Name School Team Event 3: Logic and Reasoning (with calculators) 5th/6th ...

Sequence - Find the common difference and a formula formula for the nth term of ...

maths - If told that the 3rd term of a GP is 36 and the 8th term is 8748. find ...

Math - 3,5,-5... The first term in the sequence of #'s shown above is 3. Each ...

math - in an ap the difference is between the 8th and 4th term is 20 and the 8th...