`d) 1/2x + 2 1/2 = 3 1/2x - 3/4`
`=> 1/2x + 5/2 = 7/2x - 3/4`
`=> 1/2x - 7/2x = -5/2 - 3/4`
`=> -3x = -13/4`
`=> x = -13/4 : -3`
`=> x = 13/12`
`e) 2/3x - 2/5 = 1/2x - 1/3`
`=> 2/3x - 1/2x = 2/5 - 1/3`
`=> 1/6x = 1/15`
`=> x = 1/15 : 1/6`
`=> x = 2/5`
`f) 1/3x + 2/5(x + 1) = 0`
`=> 1/3x + 2/5x + 2/5 = 0`
`=> 11/15x + 2/5 = 0`
`=> 11/15x = 0 - 2/5`
`=> 11/15x = -2/5`
`=> x = -2/5 : 11/15`
`=> x = -6/11`