Bài 2:
a: \(3x^2y\left(5xy-4xy^2+3y^2\right)\)
\(=3x^2y\cdot5xy-3x^2y\cdot4xy^2+3x^2y\cdot3y^2\)
\(=15x^3y^2-12x^3y^3+9x^2y^3\)
b: \(\left(12x^3y^2-6x^2y^3+4x^4y^4-2x^2y^2\right):\left(-2x^2y^2\right)\)
\(=-\dfrac{2x^2y^2\cdot6x-2x^2y^2\cdot3y+2x^2y^2\cdot2x^2y^2-2x^2y^2\cdot1}{2x^2y^2}\)
\(=-\left(6x-3y+2x^2y^2-1\right)\)
c: \(\left(3x+2y\right)\left(x^2-4xy-y\right)\)
\(=3x^3-12x^2y-3xy+2x^2y-8xy^2-2y^2\)
\(=3x^3-10x^2y-8xy^2-3xy-2y^2\)
d: \(\left(2x+3y\right)^2\)
\(=\left(2x\right)^2+2\cdot2x\cdot3y+\left(3y\right)^2\)
\(=4x^2+12xy+9y^2\)
e: \(\left(3y-x\right)^2\)
\(=\left(3y\right)^2-2\cdot3y\cdot x+x^2\)
\(=9y^2-6xy+x^2\)
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