First, I'll get rid of the parentheses by distributing the negative sign to each term inside them. That gives me \[2x+8x^2+9-4+2x+8x^2.\] Next, I'll look for any terms that have the same degree of $x$ and add or subtract them. I see that there are two terms with $x^2$, so I'll add them together: $8x^2+8x^2=16x^2$. I also see that there are two terms with $x$, so I'll add them together as well: $2x+2x=4x$. Finally, I'll add the constant terms: $9-4=5$. Now I have \[16x^2+4x+5.\] This is already in the form $ax^2 +bx+c$, where $a=16$, $b=4$, and $c=5$. 
Simplify the following expression in $x$: \[2x+8x^2+9-(4-2x-8x^2).\] Express your answer in the form $ax^2 +bx+c$, where $a$, $b$, and $c$ are numbers.