Sagot :
[tex](5xy - y^2) - (3yz + 2xy) + (3y^2 - 4xy) \\= 5xy-y^2-3yz-2xy+3y^2-4xy \\ =2y^2-xy-3yz[/tex]
[tex] (5xy - y^2) - (3yz + 2xy) + (3y^2 - 4xy)=\\
5xy-y^2-3yz-2xy+3y^2-4xy=\\
2y^2-xy-3yz[/tex]