Question

1)Escreva a PA em que A1=15 e a16=45

Answer 1

Razão:

45-15=30=30
16-15  1


P.a:

(15,45,75,105,135,165....)

Answer 2

an=a1+(n-1)r
a16=a1+(16-1)r
45=15+15r
30=15r
r=2

(15, 17, 19, 21, 23, 25,..., 41, 43, 45)