\begin{equation}4x^{2}+6x-6-(4x^{2}+8)\end{equation}

\begin{equation}6x^{2}y^{2}+8xy^{3}-7y^{4}-(x^{2}y^{2}-8xy^{3}+7y-9y^{4})\end{equation}

\begin{equation}4x^{3}+9x^{2}-3x+5-(3x^{3}-5x^{2}+9x-2)\end{equation}

\begin{equation}9x^{4}y+5x^{3}y^{2}-2x^{2}y^{3}-(6x^{4}y+2x^{3}y^{2}-3xy)\end{equation}

\begin{equation}2x^{2}-5x+10-(9x^{2}+8x+5)\end{equation}

\begin{equation}7x+5-(2x^{2}-7x+8)\end{equation}

\begin{equation}9A^{2}+9Ay+y-((-4)A^{2}+2Ay-6y)\end{equation}

\begin{equation}5x^{5}-3x^{4}-8-(10x^{5}+3x^{4}-8)\end{equation}

\begin{equation}(-6)x^{4}+5x^{2}y-7x+y-((-4)x^{4}-7x^{2}y+x)\end{equation}

\begin{equation}(-3)x^{2}+8xy-6y-((-10)x^{2}-4xy+10y)\end{equation}

\begin{equation}xy-7y^{2}+8xy^{3}-(9xy^{3}+4y^{2}+4xy)\end{equation}