Let's multiply the following polynomial:
[tex]\text{ \lparen5x}^2\text{ + y\rparen\lparen x}^2\text{ -2y\rparen}[/tex]
We get,
[tex]\text{ \lparen5x}^2\text{ + y\rparen\lparen x}^2\text{ - 2y\rparen= \lparen5x}^2)(\text{x}^2)\text{ + \lparen5x}^2)(-\text{2y\rparen+ \lparen y\rparen\lparen x}^2)\text{ + \lparen y\rparen\lparen-2y\rparen}[/tex][tex]\text{ = 5x}^4\text{ - 10x}^2y\text{ + x}^2y\text{ - 2y}^2[/tex][tex]\text{ = 5x}^4\text{ - 9x}^2y\text{ - 2y}^2[/tex]
