Given,
[tex]|2x+6|-4=20[/tex]On simplifying,
[tex]\begin{gathered} |2x+6|=20+4 \\ \Rightarrow|2x+6|=24 \\ 2x+6=\pm24 \end{gathered}[/tex]Thus,
[tex]\begin{gathered} 2x=+24-6 \\ \Rightarrow x=\frac{18}{2} \\ =9 \end{gathered}[/tex]Or
[tex]\begin{gathered} 2x=-24-6 \\ x=\frac{-30}{2} \\ =-15 \end{gathered}[/tex]Thus, x=9 and x=-15
Therefore the correct answer is the third option