Question

Tìm x :

a) 5^x=125

b)3^2x=81

 

Answer 1

a) 5^x = 125

5^x = 5³

=> x = 3

b) 3^2x = 81

3^2x = 3⁴

=> 2x = 4

       x = 4 : 2

       x = 2

Answer 2

a ) 5^x = 5^3

suy ra x = 3

b) 3^2x = 3^4

3^2x = 3^2.2

suy ra x = 2

Answer 3

Thanks nha 2 bạn 

Answer 4

a)5^x=125

(=)5^x=5^3

(=)x=3

vậy x = 3

b)3^2x=81

3^2x=3^4

2x=4

x=4:2

x=2

vậy x =2