Tìm x chỉ có 6 câu a b c d e f thôi mong mn giúp

`a) 210 - 5x = 200`

`=> 5x = 210 - 200`

`=> 5x = 10`

`=> x = 2`

Vậy `x=2`

`b) 210 : x - 10 = 20`

`=> 210:x = 20 + 10`

`=> 210:x = 30`

`=> x= 210 :30`

`=> x = 7`

Vậy `x = 7`

`c) 210 -5(x-10) = 200`

`=> 210- 5x +50 = 200`

`=> 260-5x = 200`

`=> 5x = 260 - 200`

`=> 5x = 60`

`=> x = 12`

vậy `x = 12`

`d) (2x +1):7 = 2^2 +3^2`

`=> (2x +1) :7 = 4+ 9`

`=> (2x + 1):7 = 13`

`=> 2x +1 = 13 . 7`

`=> 2x +1 = 91`

`=> 2x = 91 - 1`

`=> 2x = 90`

`=> x=90:2`

`=> x= 45`

Vậy `x=45`

`e) 450:[41 - (2x -5)] = 3^2 .5`

`=> 450:[41 -( 2x -5)] = 9 .5`

`=>450:[41 - (2x -5)]  = 45`

`=> 41 - (2x -5) = 10`

`=> 2x - 5 = 41 - 10`

`=> 2x = 41 -10 +5`

`=> 2x = 36`

`=> x = 18`

Vậy `x=18`

`f) (5x-39).7+3=80`

`=>(5x -39).7 = 80-3`

`=> (5x -39).7 = 77`

`=> 5x -39 = 77 : 7`

`=> 5x -39 = 11`

`=> 5x = 11 + 39`

`=> 5x = 50`

`=> x= 50 :5`

`=> x = 10`

Vậy `x = 10`

`@BestAri`