Question

15. Determine o valor das expressões
numéricas:
a) (-4/5):(+8/5)-(+2).(-5/4)
b) (-1,44) : (-2,4) + (+0,18): (-1,2)
c) (+8/5):(-4) - 6.(-1/4)​

Answer 1

Oie, Td Bom?!

a) = (- 4/5) ÷ 8/5 - 2 . (- 5/4)

= - 4/5 ÷ 8/5 - 2 . (- 5/4)

= - 4/5 ÷ 8/5 + 2 . 5/4

= - 4/5 . 5/8 + 2 . 5/4

= - 4/5 . 5/8 + 5/2

= - 4 . 1/8 + 5/2

= - 1/2 + 5/2

= (- 1 + 5)/2

= 4/2

= 2

b) = (- 1,44) ÷ (- 2,4) + 0,18 ÷ (- 1,2)

= (- 36/25) ÷ (- 12/5) + 9/50 ÷ (- 6/5)

= 36/25 ÷ (- 12/5) + 9/50 ÷ (- 6/5)

= 36/25 . 5/12 + 9/50 ÷ (- 6/5)

= 36/25 . 5/12 - 9/50 ÷ 6/5

= 36/25 . 5/12 - 9/50 . 5/6

= 3/25 . 5 - 9/50 . 5/6

= 3/5 - 9/50 . 5/6

= 3/5 - 9/10 . 1/6

= 3/5 - 3/10 . 1/2

= 3/5 - 3/20

= (12 - 3)/20

= 9/20

= 0,45

c) = 8/5 ÷ (- 4) - 6 . (- 1/4)

= - 8/5 ÷ 4 - 6 . (- 1/4)

= - 8/5 ÷ 4 + 6 . 1/4

= - 8/5 . 1/4 + 6 . 1/4

= - 8/5 . 1/4 + 3 . 1/2

= - 2/5 + 3 . 1/2

= - 2/5 + 3/2

= (- 4 + 15)/10

= 11/10

= 1,1

Att. Makaveli1996

Answer 2

Resposta:

A) -1,2

B) -0,45

C) 2,6

(MEU PROFESSOR CORRIGIU)