[tex]\qquad\qquad\huge\underline{{\sf Answer}}[/tex]
Let's evaluate ~
The given expression is :
[tex]\qquad \sf \dashrightarrow \:4x + 8[/tex]
plug the value of x as 3
[tex]\qquad \sf \dashrightarrow \:4(3) + 8[/tex]
[tex]\qquad \sf \dashrightarrow \:12 + 8[/tex]
[tex]\qquad \sf \dashrightarrow \:20[/tex]
Therefore, the required value is 20