Why are the solutions to the proportions and the same?

3= 3 ticks above 0

2.25= 2.25 ticks above 0

opposite of 4= 4 ticks below 0

-(-1 1/2)= 1.5 ticks above 0

<| - - - | - - - | - - - | - - - | - - - | - - - | - - - | - - - |>

- 4 0 1.5 2.25 3

-4 = 5.5 ticks below 1.5; 6.25 ticks below 2.25; 7 ticks below 3

1.5= 5.5 ticks above -4; 0.75 ticks below 2.25; 1.5 ticks below 3

2.25= 6.25 ticks above -4; 0.75 ticks above 1.5; 0.75 ticks below 3

3= 7 ticks above -4; 1.5 ticks above 1.5; 0.75 ticks above 2.25