`b) (1/4 . x - 1/8) . 3/4 = 1/4`
`1/4 . x - 1/8 = 1/4 ÷ 3/4`
`1/4 . x - 1/8 = 1/3`
`1/4 . x = 1/3 + 1/8`
`1/4 . x = 11/24`
`x = 11/24 ÷ 1/4`
`x = 11/6`
`c) (x - 50) ÷ 45 + 240 = 300`
`( x -50 ) ÷ 45 = 300 - 240`
`(x - 50) ÷ 45 = 60 `
`x - 50 = 60 × 45`
`x - 50 = 2700`
`x = 2700 + 50`
`x = 2750`
`d) ( 15. 19 - x - 0,15) ÷ 0,25 = 15 ÷ 0,25`
`(285 - x - 0,15) ÷ 0,25 =60`
`285 - x - 0,15 = 60 × 0,25`
`285 - x - 0,15 = 15`
`x - 0,15 = 285 - 15`
`x - 0,15 = 270`
`x = 270 + 0,15`
`x = 270,15`
`e) {[27 × 11 - (x + 12) × 18] × 3 - 79} ÷ 5 = 100`
`[27 × 11 - (x + 12) × 18] × 3 - 79 = 100 × 5`
`[27 × 11 - (x + 12) × 18] × 3 - 79 = 500`
`[27 × 11 - (x + 12) × 18] × 3 = 500 + 79`
`[27 × 11 - (x + 12) × 18] × 3 = 579`
`[27 × 11 - (x + 12) × 18] = 579 ÷ 3 `
`297 - (x + 12) × 18 = 193`
`(x + 12) × 18 = 297 - 193`
`(x+ 12) × 18 = 104`
`x + 12 = 104 ÷ 8`
`x + 12 = 13`
`x = 13 - 12`
`x = 1`
