Question

13. What is the first term of an A.P. if d=-4
n= 7 and an = 4.​

Answer 1

Answer:

tn= a + (n-1)d

4= a+(7-1)-4

4=a+(6)-4

4=a-24

4+24=a

a=28

Answer 2

Given:

Difference, d = -4

Number if terms, n = 7

Last term, An = 4

By applying last term formula:

An = a + (n - 1)d

=> 4 = a + (7 - 1)(-4)

=> 4 = a - 24

=> a = 4 + 24

=> a = 28

Therefore, first term (a) = 28