Bài 5:
a:
\(\dfrac{E}{F}=\dfrac{5x^3y^2z^2-7x^4yz^2+9x^5yz}{3x^3y^nz^m}\)
\(=\dfrac{5x^3y^2z^2}{3x^3y^nz^m}-\dfrac{7x^4yz^2}{3x^3y^nz^m}+\dfrac{9x^5yz}{3x^3y^nz^m}\)
\(=\dfrac{5}{3}y^{2-n}z^{2-m}-\dfrac{7}{3}x\cdot y^{1-n}\cdot z^{2-m}+3x^2y^{1-n}z^{1-m}\)
\(E⋮F\)
=>\(\left\{{}\begin{matrix}\left\{{}\begin{matrix}2-n>=0\\2-m>=0\end{matrix}\right.\\\left\{{}\begin{matrix}1-n>=0\\2-m>=0\end{matrix}\right.\\\left\{{}\begin{matrix}\\\end{matrix}\right.\end{matrix}\right.\) và 1-n>=0 và 1-m>=0
=>n<=1 và m<=1
=>n=1; m=1
b: Khi n=1;m=1 thì \(\dfrac{E}{F}=\dfrac{5}{3}\cdot y^{2-1}\cdot z^{2-1}-\dfrac{7}{3}\cdot x\cdot y^{1-1}\cdot z^{2-1}+3x^2y^{1-1}\cdot z^{1-1}\)
\(=\dfrac{5}{3}yz-\dfrac{7}{3}xz+3x^2\)
Bài 6:
a: \(4x^2y^3z^2:B=2xy^2z^2\)
=>\(B=\dfrac{4x^2y^3z^2}{2xy^2z^2}=\dfrac{4}{2}\cdot\dfrac{x^2}{x}\cdot\dfrac{y^3}{y^2}=2xy\)
b: \(\left(6x^3y^5+8x^2y^5-4xy^2\right):B=H+3x^2y^4-4xy^4\)
=>\(\dfrac{6x^3y^5+8x^2y^5-4xy^2}{2xy}=H+3x^2y^4-4xy^4\)
=>\(H+3x^2y^4-4xy^4=3x^2y^4+4xy^4-2y\)
=>\(H=3x^2y^4+4xy^4-2y-3x^2y^4+4xy^4\)
=>\(H=8xy^4-2y\)
