-49
Explanation:[tex]-34\text{ + 21 - 39 -(-3)}[/tex]Expanding the parenthesis:
[tex]\begin{gathered} mu\text{ltiplication of asme sign gives a positive number:} \\ -34\text{ + 21 - 39 + 3} \end{gathered}[/tex]simplify:
[tex]\begin{gathered} =-34\text{ - 39 + 21 + 3} \\ -34\text{ - 39 = - 7}3 \\ 21\text{ + 3 = 24} \end{gathered}[/tex][tex]\begin{gathered} -39\text{ - 39 + 21 + 3 = -73 + 24}| \\ =\text{ }-49 \end{gathered}[/tex]