Question

find last fifth term from the A.P -10, -8, -6,.... 88​

Answer 1

Given,

A.P -10,-8,-6,..,88

To Find,

last fifth term of the A.P

Solution,

In the given A.P

a=-8

d=2

a+(n-1)d=88

-8+(n-1)2=88

2n-2=96

2n=98

n=49

So, the fifth last term will be 45

a₄₅= a+44d

     = -8+44(2)

     = -8+88

     = 80

Therefor, the fifth last term is 80.

Answer 2

We must recall that:

Arithmetic progression is a progression in which every term after the first is obtained by adding a constant value, called the common difference (d). So, to find the nth term of an arithmetic progression, we know $an=a1+(n-1)d$

Given:

A.P $-10,-8,-6,...,888$

In the given A.P

$a=-8\\d=2$

$a+(n-1)d=88\\-8+(n-1)2=88\\2n-2=96\\2n=98\\n=49$

So, the fifth last term will be 45

$a_{45}=a+44d\\ =-8+44(2)\\=-8+88\\=80$

Therefore, the fifth last term is 80.