Question

 

Answer 1

`a, 1/20 - (x - 8/5) = 1/10`

`=> x - 8/5 = 1/20 - 1/10`

`=> x  = 1/20  - 1/10 + 8/5`

`=> x = 1/20 - 2/20 + 32/20`

`=> x = 31/20`

Vậy: `x = 31/20`

`b, 7,2 : [41 - (2x - 5)] = 2^3 . 5`

`=> 41 - (2x - 5) = 7,2 : 40`

`=> 41 - (2x - 5)= 0,18`

`=> 2x - 5 = 41 - 0,18`

`=> 2x=41-0,18+5`

`=> 2x=45,82`

`=> x=22,91`

Vậy: `x=22,91`

Answer 2

`c, |  5 - 2x| = 4`

`=> 5 - 2x = +-4`

`=> 5 - 2x = 4` hoặc `5 - 2x=  -4`

`=> 2x  = 5-4` hoặc `2x = 5 + 4`

`=> 2x = 1` hoặc `2x = 9`

`=> x = 1/2` hoặc `x = 9/2`

Vậy: `x=1/2 ; x = 9/2`

`d, (1/3)^(2x-1) = 1/243`

`=> (1/3)^(2x - 1) = (1/3)^5`

`=> 2x - 1 = 5`

`=> 2x =6`

`=> x=3`

Vậy: `x=3`

`->` Cậu hạn chế khi đăng câu hỏi sau đó thêm câu hỏi nha.

Answer 3

d,\(\left(\dfrac{1}{3}\right)^{2x-1}=\dfrac{1}{243}\)
\(\left(\dfrac{1}{3}\right)^{2x-1}=\left(\dfrac{1}{3}\right)^5\)
\(2x-1=5\)
\(2x=5+1\)
\(2x=6\)
\(x=6:2\)
\(x=3\)
Vậy \(x=3\)