Presuming you are solving for p.
[tex]4 + 3p = 19[/tex] subtract 4 from both sides.
[tex]4 + 3p - 4 = 19 - 4[/tex] simplify this, then divide both sides by 3.
[tex]\frac{3p}{3} = \frac{15}{3}[/tex] after dividing, this leaves you with
[tex]p = 5[/tex], which is the solution
p = 5
