x3 = 125
x3 = 53
x = 5
2x = 128
2x = 27
x = 7
127 < 5x < 630
127 < 625 < 630
127 < 54 < 630
x = 4
x^3=125
x^3=5^3
=> x = 5
2^x=128
2^x=2^7
=>x=7
127<5^x<630
127<5^4<630
=>x=4
x3 = 125
x3 = 53
=> x = 5
2x = 128
2x = 27
=> x = 7
127 < 5x < 630
= 53 + 2 < 5x < 54 + 5
=> x = 4
x3 = 125
x3 = 53
=> x = 5
Vậy x = 5
2x = 128
2x = 27
=> x = 7
Vậy x = 7
127 < 5x < 630
127 < 57 < 630
=> x = 7
Vậy x = 7