Bài 7: Tìm số tự nhiên x, biết : a) 6+4x = 26 b) 125 + 3x = 251 c) 70 - 5.(x-3) = 45 giúp mình nha. I love youu d) 128 - 3.(x +4 ) =23

Đáp án+Giải thích các bước giải:

 `a)`

$\text{6 + 4x = 26}$

$\text{4x = 26 - 6}$

$\text{4x = 20}$

$\text{x = 20 : 4}$

$\text{x = 5}$

`b)`

$\text{125 + 3x = 251}$

$\text{3x = 251 - 125}$

$\text{3x = 126}$

$\text{x = 126 : 3}$

$\text{x = 42}$

`c)`

$\text{70 - 5.(x - 3) = 45}$

$\text{5.(x - 3) = 70 - 45}$

$\text{5.(x - 3) = 25}$

$\text{(x - 3) = 25 : 5}$

$\text{x - 3 = 5}$

$\text{x = 5 + 3}$

$\text{x = 8}$

`d)`

$\text{128 - 3.(x + 4) = 23}$

$\text{3.(x + 4) = 128 - 23}$

$\text{3.(x + 4) = 105}$

$\text{(x + 4) = 105 : 3}$

$\text{x + 4 = 35}$

$\text{x = 35 - 4}$

$\text{x = 31}$