Question

PA (-7-3...157)
an=
a1=
n=
r=

Answer 1

a1 = -7

an = 157

$\boxed{\mathsf{r=a_{n}-a_{(n-1)}}}$

r = -3 -(-7)

r = 4

$\boxed{\mathsf{a_{n}=a_{m}+(n -m)\cdotr}}$

157 = -7 + (n -1) * 4

(157 + 7)/4 = n -1

41 + 1 = n

42 = n