Question

dada a p.a x-1/2, x+1/2,x+3/2. determine:
a) sua razao
b) o valor de x tal que a30=50

Answer 1

a)
r = a3 - a2
r = (x + 3/2) - (x + 1/2)
r = x + 3/2 - x - 1/2
r = x - x + 3/2 - 1/2
r = 3/2 - 1/2
r = 2/2
r = 1

b)
an = a1 + (n - 1) * r
a30 = x - 1/2 + (30 - 1) * 1
50 = x - 1/2 + 29 * 1
50 = x - 1/2 + 29
x = 50 + 1/2 - 29
x = 50 - 29 + 1/2
x = 21 + 1/2
x = 21 + 0,5
x = 21,5

Answer 2

Oi!!! Feliz Natal!!!
Vamos lá...
a) r = a3 - a2
r = (x + 3/2) - (x + 1/2)
r = x + 3/2 - x - 1/2
r = x - x + 3/2 - 1/2
r = 2/2
r = 1

b) an= a1 + (n - 1) . r
a30= x - 1/2 + (30 - 1) . 1
50= x - 1/2 + 29 . 1
50= x - 1/2 + 29
x= 50 + 1/2 - 29
x= 50 - 29 + 1/2
x= 21 + 1/2
x= 21 + 0,5
x= 21, 5
Bons Estudos...