Just plug in the value and simplify:
[tex]\sf 3d-4[/tex]
[tex]\sf 3(1.2)-4[/tex]
Multiply:
[tex]\sf 3.6-4[/tex]
Subtract:
[tex]\boxed{\sf -0.4}[/tex]
[tex]\sf\dfrac{2}{3}p+3[/tex]
[tex]\sf\dfrac{2}{3}(\dfrac{3}{5})+3[/tex]
Multiply:
[tex]\sf \dfrac{6}{15}+3[/tex]
Simplify:
[tex]\boxed{\sf 3\dfrac{2}{5}}[/tex]