Question

[Thư Phạm]

Thực hiện phép tính 
1) (x-y).(6x²-4y²+\(\dfrac{1}{2}\)xy)
2) (6x-1).(3+x)+(2x+5).(-3x)

Answer 1

[Tô Mì]

1. \(\left(x-y\right)\left(6x^2-4y^2+\dfrac{1}{2}xy\right)\)

\(=6x^3-4xy^2+\dfrac{1}{2}x^2y-6x^2y+4y^3-\dfrac{1}{2}xy^2\)

\(=6x^3+4y^3-\dfrac{11}{2}x^2y-\dfrac{9}{2}xy^2\)

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2. \(\left(6x-1\right)\left(3+x\right)+\left(2x+5\right)\left(-3x\right)\)

\(=18x+6x^2-3-x-6x^2-15x\)

\(=2x-3\)

Chúc bạn học tốt!