To add the polynomial expressions \( 3 - 2p - 5p^2 \) and \( p^4 - 3p + 4 \), you need to combine like terms:
- Write the two polynomials one under the other, aligning like terms:
\[ \begin{array}{r} 3 \ -2p \ -5p^2 \ \hline \end{array} + \begin{array}{r} p^4 \ -3p \ 4 \ \hline \end{array} \]
- Now, combine all the like terms:
- The highest degree term is \( p^4 \).
- The \( p^2 \) term is \( -5p^2 \).
- The \( p \) terms are \( -2p - 3p = -5p \).
- The constant terms are \( 3 + 4 = 7 \).
Putting it all together, we get:
\[ p^4 - 5p^2 - 5p + 7 \]
Thus, the sum of the polynomials \( 3 - 2p - 5p^2 \) and \( p^4 - 3p + 4 \) is:
\[ \boxed{p^4 - 5p^2 - 5p + 7} \]