1 tìm x a. 3.(2x+1) -19=14 b.541 +(218 -x)=735 c.125:(3x -13)=25 d.175-5.(x+3)=85

`a) 3 . (2x + 1) - 19 = 14`

`3 . (2x + 1) = 14 + 19`

`3 . (2x + 1) = 33`

`2x + 1 = 33 : 3`

`2x + 1 = 11`

`2x = 11 - 1`

`2x = 10`

`x = 10 : 2`

`x = 5.`

`b) 541 + (218 - x) = 735`

`218 - x = 735 - 541`

`218 - x = 194`

`x = 218 - 194`

`x = 24.`

`c) 125 : (3x - 13) = 25`

`3x - 13 = 125 : 25`

`3x - 13 = 5`

`3x = 5 + 13`

`3x = 18`

`x = 18 : 3`

`x = 6.`

`d) 175 - 5 . (x + 3) = 85`

`5 . (x + 3) = 175 - 85`

`5 . (x + 3) = 90`

`x + 3 = 90 : 5`

`x + 3 = 18`

`x = 18 - 3`

`x = 15.`

$\text{#lknhatminh0322}$