Question

QUANTOS TERMOS POSSUI A PA (-5,2,....,65)?

Answer 1

a1=   -5
an= 65
r= razao = 2-(-5)=  2+5=7
an= a1+(n-1).r
65= -5+(n-1)7
65= .5+7n-7
65+5+7=7n
7n=77
n= 77:7
n= 10  10 termos tem a pa