Đáp án:
$\begin{array}{l}
e)\left( {25{x^2}y - 13x{y^2} + {y^3}} \right) - \left( {11{x^2}y - 2{y^3}} \right)\\
= 25{x^2}y - 13x{y^2} + {y^3} - 11{x^2}y + 2{y^3}\\
= 14{x^2}y - 13x{y^2} + 3{y^3}\\
f)\left( {3{x^2} - 2xy + {y^2}} \right) + \left( {{x^2} - xy + 2{y^2}} \right) - \left( {4{x^2} - {y^2}} \right)\\
= 3{x^2} - 2xy + {y^2} + {x^2} - xy + 2{y^2} - 4{x^2} + {y^2}\\
= - 3xy + 2{y^2}\\
g)\left( {{x^2} + {y^2} - 2xy} \right) - \left( {{x^2} + {y^2} + 2xy} \right) + \left( {4xy - 1} \right)\\
= - 4xy + 4xy - 1\\
= - 1\\
h)\left( {{x^2} + {y^2} - 2x{y^2}} \right) - \left( {6{x^2} - 3x{y^2}} \right)\\
= {x^2} + {y^2} - 2x{y^2} - 6{x^2} + 3x{y^2}\\
= {y^2} - 5{x^2} + x{y^2}\\
i)5xy + {x^2} - 7{y^2} + \left( {2xy - 4{y^2}} \right)\\
= 5xy + {x^2} - 7{y^2} + 2xy - 4{y^2}\\
= 7xy + {x^2} - 11{y^2}\\
j) - 2{x^3} + x{y^2} + 3x - \left( {3{x^3} - x{y^2} + 4x} \right)\\
= - 5{x^3} + 2x{y^2} - x
\end{array}$
