\begin{equation}9x^{2}+10x-9-(8x^{2}+7)\end{equation}

\begin{equation}7x^{2}y^{2}+6xy^{3}-10y^{4}-(x^{2}y^{2}-7xy^{3}+8y-4y^{4})\end{equation}

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

\begin{equation}9x^{4}y+4x^{3}y^{2}-8x^{2}y^{3}-(8x^{4}y+9x^{3}y^{2}-5xy)\end{equation}

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

\begin{equation}4x+9-(7x^{2}-5x+4)\end{equation}

\begin{equation}4A^{2}+7Ay+y-((-4)A^{2}+9Ay-5y)\end{equation}

\begin{equation}3x^{5}-2x^{4}-2-(10x^{5}+3x^{4}-7)\end{equation}

\begin{equation}(-6)x^{4}+9x^{2}y-4x+y-((-2)x^{4}-10x^{2}y+x)\end{equation}

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

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