Đáp án:
$5) E=-5050\\
6) F=204\\
7) G=2$
Giải thích các bước giải:
$5) E=x(x^2-y^2)-x^2(x+y)+y(x^2-x)\\
=x(x-y)(x+y)-x^2(x+y)+y(x^2-x)\\
=(x+y)(x^2-xy-x^2)+y(x^2-x)\\
=-xy(x+y)+xy(x-1)\\
=xy(-x-y+x-1)\\
=xy(-y-1)\\
\Rightarrow E=\frac{1}{2}.100.(-100-1)\\
=50.(-101)=-5050\\
6) F=4x^2(5x-3y)-5x^2(4x+y)\\
=20x^3-12x^2y-20x^3-5x^2y\\
=-17x^2y\\
\Rightarrow F=(-17).(-2)^2.(-3)=(-17).4.(-3)=17.4.3=204\\
7) G=(x^2y+y^3)(x^2+y^2)-y(x^4+y^4)\\
=x^4y+x^2y^3+x^2y^3+y^5-x^4y-y^5\\
=2x^2y^3\\
\Rightarrow G=2.0,5^2.(-2)^2=2.\frac{1}{4}.4=2$
