Question

quantos termos tem a p.a (7,11,...,43)! conta​

Answer 1

an= a1+(n-1).r

razão=r= 11-7=4

an=43

a1=7

Portanto:

43= 7+(n-1).4

43= 7+4n-4

43= 3+4n

43-3=4n

40= 4n

40/4=n

n= 10

PA( 7, 11, 15 , 19, 23, 27, 31, 35, 39, 43)

Answer 2

resolução!

r = a2 - a1

r = 11 - 7

r = 4

an = a1 + ( n - 1 ) r

43 = 7 + ( n - 1 ) 4

43 = 7 + 4n - 4

43 = 3 + 4n

43 - 3 = 4n

40 = 4n

n = 40 / 4

n = 10