Question

if the first and last term of an apre 10 and (-10) how many terms there d=(-1)​

Answer 1

Step-by-step explanation:

putting the values in formula and solving further.

Answer 2

Answer:

a1 = 10, an = -10, d = -1

an = a + (n -1) d

-10 = 10 + (n-1) × -1

-10 = 10 -1n + 1

-10 = 10 + 1 -1n

-10 = 11 - 1n

-11 -10 = - 1n

-21 = -1n

21 = n