Question

Làm tính nhân :

a) \(\left(x^2-1\right)\left(x^2+2x\right)\)

b) \(\left(x+3y\right)\left(x^2-2xy+y\right)\)

c) \(\left(2x-1\right)\left(3x+2\right)\left(3-x\right)\)

Answer 1

a) \((x^2-1)(x^2+2x) =x^4+2x^3-x^2-2x\)

b) \((x+3y)(x^2-2xy+y) = x^3- 2x^2y+xy+3x^2y-6xy^2+3y^2\)

=\(x^3+xy+x^2y+6xy^2+3y^2\)

c) \((2x-1)(3x+2)(3-x)=6x^2+4x+6x-2x^2-3x-2-3+x\)= \(4x^2+8x-5\)\(\)

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