Question

qual o quarto termo da PA (1-3×,×-2,2×+1...)

Answer 1

r=2x+1-(x-2)
r=2x+1-x+2
r=x+3


r=x-2-(1-3x)
r=x-2-1+3x
r=4x-3

x+3=4x-3
6=3x
x=2

vamos achar o termos

a1=1-3x
a1=1-6=-5

a2=x-2
a2=2-2=0

a3=2x+1
a3=4+1=5

r=a3-a2
r=5-0=5

logo o quarto termo será
a4=a3+r
a4=5+5=10