Question

1. Identify the 42nd term of an arithmetic sequence where a1 = -12 and a27 = 66.

Answer 1

the nth term in a AP are given by:

a+(n-1)d

where a is the first term and d is the common difference.

Here we have the first term being -12 ie a = -12.

27th term is 66, so we have:

-12+(27-1)d=66
26d=66+12=78
d=78/26=3

Therefore the nth term is:

-12+3(n-1)

So the 42nd term is:

-12+3(42-1)=111

Answer 2

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