[tex]\begin{gathered} 14x^2+13x+12-7x^2-20x-4 \\ \text{Note that the negative sign in front of the parenthesis multiplies all the terms in the parenthesis} \\ \text{collect like terms and you have} \\ 14x^2-7x^2+13x-20x+12-4 \\ 7x^2-7x+8 \end{gathered}[/tex]
