[tex]3p* (2+k) = 6p + 3pk[/tex]
Subtract [tex]6 p + 3 pk[/tex] from the both sides:
[tex]3p(2+k) -(6p+3pk) = 6p+3pk-(6p+3pk)[/tex]
[tex]= 3pk(2+k) - 6p-3pk = 0[/tex]
Factor [tex]3p(2+k) - 6p - 3k[/tex]
Factor out common term [tex]3p[/tex]
[tex]= 3p(k-k+2-2)[/tex]
refine:
[tex]0 = 0[/tex]
true for all [tex]p[/tex]
hope this helps!