whoops almost forgot :P. deriving equations 3 and 4!

So Equations 3 and 4 are basically what Mr.Chung calls "Twins" so they are basically the same except that one is  V_{1 and the other is} V₂


How to transform from Equations 1 and 2 to Equations 3 and 4:
Equation 1: V₂₌ V_1+at
Equation 2: d= ^1/₂  (V₂ -V₁ )t

3:

Sub (at) for (V₂ -V₁ ) from equation 2_: d= ^1/₂  (V₂ -V₁ )t   +    V₁ t

 d= ^1/₂  (at)t   +    V₁ t

  d= ^1/₂   a t²   +    V₁ t

 d=  V₁ t  +   ^1/₂   a t² 

4:

d= V₂ t - ^1/₂  (V₂ -V₁ )t
Sub (at) for (V₂ -V₁ ) from equation 2
d= V₂ t - ^1/₂  (at )t
d= V₂ t - ^1/₂  a t²