Bài 1 Tìm x biết a, 400 - 3x = 100 b, 250 : x + 15 = 25 c, 96 - 3 ( x + 8 )= 42 d ,36 : ( x - 5 ) = 2² e , 15 . 5 ( x - 25 ) = 225 = 0

`a, 400 - 3x = 100`

`=> 3x= 400-100=200`

`=> x = 200:3=200/3`

Vậy `x=200/3`

`b, 250 : x + 15 = 25`

`=> 250:x = 25-15 = 10`

`=> x = 250:10=25`

Vậy `x=25`

`c, 96 - 3 ( x + 8 )= 42`

`=> 3(x+8) = 96  -42 = 54`

`=> x + 8 = 54:3 = 18`

`=> x = 18-8=10`

Vậy `x=10`

`d ,36 : ( x - 5 ) = 2^2 =4`

`=> x-5 =36:4 = 9`

`=> x = 9+5=14`

Vậy `x=14`

`e , 15 . 5 ( x - 25 ) = 225`

`=> x-25 = 225:75 = 3`

`=> x = 3+25=28`

Vậy `x = 28`

Đề `ne`

`15.5(x-25) = 0`

`=> x  -25 = 0`

`=> x= 25`

Vậy `x=25`