Question

Tìm X thuộc N biết:

a) (2 . x +1)^3=125

b) (4 . x-1)^2=25.9

 

Answer 1

a,(2.x+1)^3=125

(2.x+1)^3=5^3

Suy ra 2x+1=5

2x=5-1

2x=4

x=4:2

x=2

b,(4.x-1)^2=25.9

(4.x-1)^2=225

(4.x-1)^2=15^2

Suy ra 4.x-1=15

4x=15+1

4x=16

x=16:4

x=4

Answer 2

a) \(\left(2x+1\right)^3=125=5^3\)=> 2x + 1 = 5 => x = 2

b) \(\left(4x-1\right)^2=25.9=15^2\)=> 4x - 1 = 15 => x = 4

Answer 3

2a) (2x + 1)^3 = 125​ (2x + 1)^3 = 5^3​2x + 1 = 5​2x = 5 + 1​2x = 6x = 6:2= 3​