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a) \(x^3\left(3x^2-x-\dfrac{1}{2}\right)=3x^5-x^4-\dfrac{1}{2}x^3\)
b) \(\left(5xy-x^2+y\right)\dfrac{2}{5}xy^2=2x^2y^3-\dfrac{2}{5}x^3y^2+\dfrac{2}{5}xy^3\)
c) \(\left(4x^3-3xy^2+2xy\right)\left(-\dfrac{1}{3}x^2y\right)=\dfrac{-4}{3}x^5y+x^3y^3-\dfrac{2}{3}x^3y^2\)
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a) -5xy(3x2y – 5xy +y2)
=-15x3y2+25x2y2-5xy3
b) (x + 8)2 -2(x + 8) (x – 2) + (x – 2)2
=[(x+8)-(x-2)]2
=(x+8-x+2)2
=102
=100
\(a,-5xy\left(3x^2y-5xy+y^2\right)=-15x^3y^2+25x^2y^2-5xy^3\)
\(b,\left(x+8\right)^2-2\left(x+8\right)\left(x-2\right)+\left(x-2\right)^2=\left[x+8-\left(x-2\right)\right]^2=\left[x+8-x+2\right]^2=10^2=100\)
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3(x2-2xy+y2):10(x-y)
3(x-y)2:10(x-y)
3(x-y):10
5(x2-xy+y2):(x+y)(x2-xy+y2)
5:x+y
ở nơi 5y thiếu ^2 nhé
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\(\left(3x^2-5xy^3\right)\left(3x^2+5xy^3\right)\)
\(=\left(3x^2\right)^2-\left(5xy^3\right)^2\)
\(=9x^4-25x^2y^6\)
\(\left(3x^2-5xy^3\right)\left(3x^2+5xy^3\right)\\ =9x^4-25x^2y^6\)