\begin{equation}2x^{2}+5x-10-(8x^{2}+6)\end{equation}

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

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

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

\begin{equation}10x^{2}-7x+9-(3x^{2}+2x+5)\end{equation}

\begin{equation}2x+8-(3x^{2}-3x+5)\end{equation}

\begin{equation}2A^{2}+7Ay+y-((-8)A^{2}+7Ay-4y)\end{equation}

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

\begin{equation}(-8)x^{4}+5x^{2}y-2x+y-((-10)x^{4}-3x^{2}y+x)\end{equation}

\begin{equation}(-7)x^{2}+10xy-6y-((-6)x^{2}-10xy+4y)\end{equation}

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