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(X+3y)^2
(X-5xy)^2
(5+9y)^3
(6x-7xy)^3
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MK
1
DD
Đoàn Đức Hà
Giáo viên
12 tháng 4 2021
\(A=\left(-6x^7y^6\right)\left(8x^3y^3\right)=\left(-6.8\right).\left(x^7.x^3\right).\left(y^6.y^3\right)=-48x^{10}y^9\).
\(B=-7xy^2-2xy+6xy^2+5xy+6=\left(-7xy^2+6xy^2\right)+\left(-2xy+5xy\right)+6=-xy^2+3xy+6\)
GM
1
7 tháng 12 2021
\(5xy\left(2x^3y^2-7xy+3y\right)=10x^4y^3-35x^2y^2+15xy^2\\ \left(-6x^6+15x^2-4x^4\right):3x^2=-2x^4+5-\dfrac{4}{3}x^2\\ \left(x^2-y^2-12x+36\right):\left(x+y-6\right)\\ =\left[\left(x-6\right)^2-y^2\right]:\left(x+y-6\right)\\ =\left(x-y-6\right)\left(x+y-6\right):\left(x+y-6\right)\\ =x-y-6\)
Q
20 tháng 6 2017
a) \(\left(2x^3-y^2\right)^3\)
\(=\left(2x^3\right)^3-3\cdot\left(2x^3\right)^2\cdot y^2+3\cdot2x^3\cdot\left(y^2\right)^{^2}-\left(y^2\right)^3\)
\(=8x^9-3\cdot4x^6y^2+3\cdot2x^3y^4-y^6\)
\(=8x^9-12x^6y^2+6x^3y^4-y^6\)
b) \(\left(x-3y\right)\left(x^2+3xy+9y^2\right)\)
\(=x^3-\left(3y\right)^3\)
\(=x^3-27y^3\)
c) \(\left(x+2y+z\right)\left(x+2y-z\right)\)
\(=\left(x+2y\right)^2-z^2\)
\(=x^2+4xy+4y^2-z^2\)
d) \(\left(2x^3y-0,5x^2\right)^3\)
\(=\left(2x^3y-\dfrac{1}{2}x^2\right)^3\)
\(=8x^9y^3-6x^8y^2+\dfrac{3}{2}x^7y-\dfrac{1}{8}x^6\)
e) \(\left(x^2-3\right)\left(x^4+3x^2+9\right)\)
\(=\left(x^2-3\right)\left(4x^2+9\right)\)
\(=4x^4+9x^2-12x^2-27\)
\(=4x^4-3x^2-27\)
f) \(\left(2x-1\right)\left(4x^2+2x+1\right)\)
\(=\left(2x\right)^3-1^3\)
\(=8x^3-1\)
TN
20 tháng 6 2017
\(a,\left(2x^3-y^2\right)^3=8x^9-12x^6y^2+6x^3y^4-y^6\)\(b,\left(x-3y\right)\left(x^2+3xy+9y^2\right)=x^3-27y^3\)
\(c,\left(x+2y+z\right)\left(x+2y-z\right)=\left(x+2y\right)^2-z^2=x^2+4xy+4y^2-z^2\)\(d,\left(2x^3y-0,5x^2\right)^3=8x^9y^3-6x^4y^2x^2+3x^3yx^4-0,125x^6=8x^9y^3-6x^6y^2+3x^7y-0,125x^6\)
30 tháng 5 2023
a: =>A-B=3x^2y-4xy^2+x^2y-2xy^2=4x^2y-6xy^2
b: =>B-A=-7xy^2+8x^2y-5xy^2+6x^2y=-12xy^2+14x^2y
=>A-B=12xy^2-14x^2y
c: =>B-A=8x^2y^3-4x^3y-3x^2y^3+5x^3y^2=5x^2y^3+x^3y^2
=>A-B=-5x^2y^3-x^3y^2
d: =>A-B=2x^2y^3-7x^3y+6x^2y^3+3x^3y^2=8x^2y^3-7x^3y+3x^3y^2
HN
20 tháng 6 2018
a) \(\left(2x^3y-0,5x^2\right)^3\)
\(=\left(2x^3y\right)^3-3\left(2x^3y\right)^20,5x^2+3.2x^3y\left(0,5x^2\right)^2-\left(0,5x^2\right)^3\)
\(=8x^9y^3-6x^8y^2+1,5x^7y-0,125x^6\)
b) \(\left(x-3y\right)\left(x^2+3xy+9y^2\right)\)
\(=x^3-\left(3y\right)^3\)
\(=x^3-27y^3\)
c) \(\left(x^2-3\right)\left(x^4+3x^2+9\right)\)
\(=x^3-3^3\)
\(=x^3-27.\)
19 tháng 6 2018
a,\(\left(2x^3y-0,5x^2\right)^3=\left(2x^3y\right)^3-3.\left(2x^3y\right)^2.\left(0,5x^2\right)+3.\left(0,5x^2\right)^2.\left(2x^3y\right)-\left(0,5x^2\right)^3\)
\(=8x^9y^3-6x^8y^2+\frac{3}{2}x^7y-\frac{1}{8}x^6\)
b,\(\left(x-3y\right)\left(x^2+3xy+9y^2\right)=\left(x-3y\right)\left[x^2+x.3y+\left(3y\right)^2\right]\)
\(=x^3-\left(3y\right)^3=x^3-27y^3\)
\(\left(x^2-3\right)\left(x^4+3x^2+9\right)=\left(x^2-3\right)\left[\left(x^2\right)^2+3.x^2+3^2\right]\)
\(=\left(x^2\right)^3-3^3=x^6-27\)
\((x+3y)^2\\=x^2+2\cdot x\cdot3y+(3y)^2\\=x^2+6xy+9y^2\\---\\(x-5xy)^2\\=x^2-2\cdot x\cdot5xy+(5xy)^2\\=x^2-10x^2y+25x^2y^2\)
\((5+9y)^3\\=5^3+3\cdot5^2\cdot9y+3\cdot5\cdot(9y)^2+(9y)^3\\=125+675y+1215y^2+729y^3\\---\\(6x-7xy)^3\\=(6x)^3-3\cdot(6x)^2\cdot7xy+3\cdot6x\cdot(7xy)^2-(7xy)^3\\=216x^3-756x^3y+882x^3y^2-343x^3y^3\)