a) X:15+42=15+25.8

b) (x+40).15=75.24

c) [(x+12)-17]:5=4

d) (x-32) -15=0

e) 456-(x+23) =326

f) 234+(345-x) =500

Giúp em với ak

$#Lemon$ gửi cou cìa`.`

`a,` `x : 15 + 42 = 15 + 25.8.`

`x : 15 + 42 = 15 + 200.`

`x : 15 + 42 = 215.`

`x : 15 = 215 - 42.`

`x : 15 = 173.`

         `x = 173 xx 15.`

           `x = 2595.`

Vậy `x = 2595.`

`b,` `( x + 40 ).15 = 75.24.`

`( x + 40 ). 15 = 1800.`

`x + 40 = 1800 : 15.`

`x + 40 = 120.`

`x = 120 - 40.`

`x = 80.`

Vậy `x = 80.`

`c,` `[ ( x + 12 ) - 17 ] : 5 = 4.`

`[ ( x + 12 ) - 17 ] = 4 xx 5.`

`[ ( x + 12 ) - 17 ] = 20.`

`( x + 12 ) - 17 = 20.`

`x + 12 = 20 + 17.`

`x + 12 = 37.`

`x = 37 - 12.`

`x = 25.`

Vậy `x = 25.`

`d,` `( x - 32 ) - 15 = 0.`

`x - 32 = 0 + 15.`

`x - 32 = 15.`

`x = 15 + 32.`

`x = 47.`

Vậy `x = 47.`

`e,` `456 - ( x + 23 ) = 326.`

`x + 23 = 456 - 326.`

`x + 23 = 130.`

`x = 130 - 23.`

`x = 107.`

Vậy `x = 107.`

`f,` `234 + ( 345 - x ) = 500.`

`345 - x = 500 - 234.`

`345 - x = 266.`

`x = 345 - 266.`

`x = 79.`

Vậy `x = 79.`