1) Since it's been given the value for p=2, then let's plug into each expression to find the value of those.
4(p-5)-8 Plug into that p=2
4(2-5) -8 Parentheses first
4(-3) -8 distribute the factor
-12 -8
-20
2) Now let's plug p=2 into 4p-28
4p-28
4(2) -2