Question

!!!!URGENTE!!!!

Determine o x em cada PA:

a) (x, 5, 12)
b) (-5, x, 8)
c) (2/3, x, 7/2)
d) (3/2, 1/5, x)
e) (x, -2, -7/2
f) (5/8, x, -1/2)
g) (1/4, x, -2)
h) (3/5, x, 2/5)

Answer 1

Resposta:

Explicação passo-a-passo:

PA:

{a₁, a₂, a₃ ... aₙ)

r=a₂-a₁=a₃-a₂=⋯=aₙ-a₍ₙ₋₁₎, onde r é a razão

a₂=(a₁+a₃)/2

a) (x, 5, 12)

5-x=12-5

5-x=7

x=5-7

x= -2

b) (-5, x, 8)

x-(-5)=8-x

x+5=8-x

x+x=8-5

2x=3

x=3/2

c) (2/3, x, 7/2)

x=(7/2+2/3)/2=[(21+4)/6]/2=25/6.1/2=25/12

d) (3/2, 1/5, x)

1/5-3/2=x-1/5

(2-15)/10=(5x-1)/5

-13=2(5x-1)

-13=10x-2

10x=2-13

10x= -11

x= -11/10

e) (x, -2, -7/2)

-2-x= -7/2-(-2)

-2-x= -7/2+2

-4-2x= -7+4

2x= -4+3

x= -1/2

f) (5/8, x, -1/2)

x-5/8= -1/2-x

8x-5= -4-8x

16x= -4+5

x= 1/16

g)(1/4, x, -2)

x=[1/4+(-2)]/2

x=[(1-8)/4]/2

x= -7/4.1/2

x= -7/8

h) (3/5, x, 2/5)

x=[3/5+2/5]/2

x=1/2