Question

if the first term of an AP is 22,the common difference is -4 and sum to n terms is 24, find the number of terms.​

Answer 1

Step-by-step explanation:

Firts term =a=22

Common difference d==−4

Sum =S=64

S=

2

n

(a+a+(n−1)d)

S=

2

n

(2a+(n−1)d)

64=

2

n

(44+(n−1)(−4))

128=n(44−4n+4)

128=n(48−4n)

128=48n−4n

2

4n

2

−48n+128=0

n

2

−12n+32=0

n=

2

+12±

12

2

−4×32

n=

2

+12±

144−128

n=

2

+12±

16

n=

2

1. +12±4

• n=8 or b=4

Answer 2

Answer:

the number of terms is 8..