Question

In an ap, if the common difference (d)=-4, and the seventh term (a7) is 4, then find the firsy term

Answer 1

As we know that seventh term is (a+6d)

Now,

difference = -4

first term = a

Then

a+ (6*[-4]) = 4

a + (-24) = 4

a -24 = 4 

a = 4+24

a =28

then,

first term is  28


i hope this will help you



-by ABHAY

Answer 2

Hey friend, Harish here.

Here is your answer:

Given that,

1) Common difference of AP (d) = -4.

2) Seventh term of the AP = 4.

To find,

The first term of the AP.

Solution,

We know that,

$S_7=(a+6d)$

⇒ $4 = a + 6\times (-4)$

⇒ $4 = a-24$

⇒ $a = 24 + 4 = 28.$

Therefore the first term is 28.
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Hope my answer is helpful to you.