tìm số nguyên x biết ( - 400 ) : 20 + 5 . ( 4 x - 1 ) = 15

2 câu trả lời

`(-400) : 20 + 5.(4x - 1) =15`

`=> (-20) + 5.(4x - 1) = 15`

`=> 5.(4x - 1) = 15 - (-20)`

`=> 5.(4x - 1) = 35`

`=> 4x - 1 = 35 : 5`

`=> 4x - 1 = 7`

`=> 4x = 7 + 1`

`=> 4x = 8`

`=> x =8 : 4`

`=> x = 2`

Vậy `x = 2`

`#dtkc`

`@` Tham khảo `@`

`(-400):20+5.(4x-1)= 15`

`(-20)+5.(4x-1)= 15`

`5.(4x-1)= 15-(-20)`

`5.(4x-1)= 15+20`

`5.(4x-1)= 35`

`4x-1= 35:5`

`4x-1= 7`

`4x= 7+1`

`4x= 8`

`x= 8:4`

`x= 2`

Vậy `x= 2`

`#Jo`