Question

Given an arithmetic sequence where a1=5 and a9=-19 find a42

Answer 1

Answer:

-76/8 = -19/2

In an arithmetic sequence, the nth term, an, is given by the formula:

an = a1 + (n - 1)d, where a1 is the first term and d is the common difference.  

So, a9 = a1 + 8d

Substituting in the given data, 12 = 88 + 8d

                                                    -76 = 8d

                                                      d = -76/8 = -19/2

Step-by-step explanation:

i hoped this helped!

Answer 2

A1=a=5
a9=a+8d=-19
Since a=5
5+8d=-19
8d=-19-5
8d=-24
d=-24/8
d=-3
a42=a+41d
a42= 5+(41*5)
a42=5+205
a42=210