Найтии d. 1)a1=2, a10=92. 2)a1=-7, a16=2 3)a1=0, a66=-92 Сроочно помогите людям

Question

Найтии d.
1)a1=2, a10=92.
2)a1=-7, a16=2
3)a1=0, a66=-92
Сроочно помогите людям

Answer 1

1) a10 = a1+9d
9d = a10-a1
d = (a10-a1)/9
a = (92-2)/9 = 10

2) a16 = a1 + 15d
15d = a16-a1
d = (a16-a1)/15
d = (2 - (-7))/15 = 9/15 = 3/5 

3) a66 = a1 + 65d
65d=a66-a1
d = (a66-a1)/65
d = (-92 - 0) / 65 = -92/65 = -1  27/65