Respuesta :
So you can use substitution for this problem which is plugging in the 4 for x:
3(4)+9
then you know that you can simplify it even more to
12+9
that can be simplified even more to
21
which is in simpliest form
3(4)+9
then you know that you can simplify it even more to
12+9
that can be simplified even more to
21
which is in simpliest form