Respuesta :

We have

4b

And the opposite of "4b + 20" is:

[tex]\begin{gathered} -(4b+20) \\ -4b-20 \end{gathered}[/tex]

We can write the sum of these 2 expressions as:

[tex]\begin{gathered} (4b)+(-4b-20) \\ =4b-4b-20 \\ =-20 \end{gathered}[/tex]