Bài 11:
a: \(\left(3x^5-5x^6-7x^3\right):5x^2\)
\(=\frac{3x^5}{5x^2}-\frac{5x^6}{5x^2}-\frac{7x^3}{5x^2}\)
\(=\frac35x^3-x^4-\frac75x\)
b: \(\left(5x^6y^7+4x^5y^6+3x^4y^5\right):\left(-x^3y^2\right)\)
\(=-\frac{5x^6y^7}{x^3y^2}-\frac{4x^5y^6}{x^3y^2}-\frac{3x^4y^5}{x^3y^2}\)
\(=-5x^3y^5-4x^2y^4-3xy^3\)
c: \(\left(\frac58x^5y^8-5x^4y^2+\frac79x^7y^9\right):\frac53x^3y\)
\(=\frac58x^5y^8:\frac53x^3y-5x^4y^2:\frac53x^3y+\frac79x^7y^9:\frac53x^3y\)
\(=\frac38x^2y^7-3xy+\frac{7}{15}x^4y^8\)
d: \(\left(x^3y^4z^2-2x^4y^2z^4+7x^5y^2z^3\right):x^2y^2z^2\)
\(=\frac{x^3y^4z^2}{x^2y^2z^2}-\frac{2x^4y^2z^4}{x^2y^2z^2}+\frac{7x^5y^2z^3}{x^2y^2z^2}\)
\(=xy^2-2x^2z^2+7x^3z\)
Bài 10:
a: (2x+7)(3x-1)
\(=6x^2-2x+21x-7\)
\(=6x^2+19x-7\)
b: \(\left(5x-2y\right)\left(x^2-xy+1\right)\)
\(=5x^3-5x^2y+5x-2x^2y+2xy^2-2y\)
\(=5x^3-7x^2y+2xy^2+5x-2y\)
c: (x-1)(x+1)(x+2)
\(=\left(x^2-1\right)\cdot\left(x+2\right)\)
\(=x^3+2x^2-x-2\)
d: \(\left(5x^2-4x\right)\left(2x^2+9x-3\right)\)
\(=10x^4+45x^3-15x^2-8x^3-36x^2+12x\)
\(=10x^4+37x^3-51x^2+12x\)
Bài 9:
a: \(\left(x-y\right)\left(x^3+x^2y+xy^2+y^3\right)\)
\(=x^4+x^3y+x^2y^2+xy^3-x^3y-x^2y^2-xy^3-y^4\)
\(=x^4-y^4\)
em cần giải gấp bài 3 chi tiết mọi người giúp em với ạ. Làm bài dưới dạng phân số ạ em cần gấp
