Question

Answer 1

Bài 1

a) 2/9 : (1/2)²

= 2/9 : 1/4

= 8/9

b) 2/5 . 3/8 - 2/5 . (-10/8) + 2/5 . 1/4

= 2/5 . (3/8 + 10/8 + 1/4)

= 2/5 . 15/8

= 3/4

c) 1/2 . 2³ - 2/5 - |-4|

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

= 4 - 2/5 - 4

= (4 - 4) - 2/5

= -2/5

Answer 2

Bài 2

a) 2x + 3,5 = 15/2

2x + 7/2 = 15/2

2x = 15/2 - 7/2

2x = 4

x = 4 : 2

x = 2

b) (2/3 - 2x)³ = 8

(2/3 - 2x)³ = 2³

2/3 - 2x = 2

2x = 2/3 - 2

2x = -4/3

x = -4/3 : 2

x = -2/3

c) |x + 1| - 2³ = 0

|x + 1| - 8 = 0

|x + 1| = 0 + 8

|x + 1| = 8

*) Với x ≥ -1 ta có:

x + 1 = 8

x = 8 - 1

x = 7 (nhận)

*) Với x < -1 ta có:

x + 1 = -8

x = -8 - 1

x = -9 (nhận)

Vậy x = -9; x = 7