Question

(5^x-1).3_2=70

Answer 1

(5^x-1).3-2=70

(5^x-1).3=70+2

(5^x-1).3=72

5^x-1=72:3

5^x-1=24

5^x=24+1

5^x=25

Mà 25=5²

Suy ra x=2

Answer 2

Dấu _ nghĩa là sao

Answer 3

dau (_) la ?????????????

Answer 4

(5^x - 1) . 3 - 2 = 70

(5^x - 1) . 3 = 72

5^x - 1 = 24

5^x = 25

5^x = 5²

=> x = 2