Question

determine o termos da P.A

(3,11,19,..,115)

(86,83,80,..,35)

(-8,-5,-2,..,22)​

Answer 1

(3,11,19,..,115)

an=a1+(n-1).r

115=3+(n-1).8

115=3+8n-8

8n=115+5

8n=120

n=120/8= 15 termos

(86,83,80,..,35)

an=a1+(n-1).r

35=86+(n-1).(-3)

35=86+3-3n

3n=86+3-35

3n=54

n=54/3 = 18 termos

(-8,-5,-2,..,22)

an=a1+(n-1).r

22=-8+(n-1).​3

22=-8+3n-3

3n=22+11

3n=33

n=33/3 = 11 termos