Question

Phân tích đa thức thành nhân tử :

a) x²-2x-15

b) y.(x-z)+7(z-x)

c) 27x²(y-1)-9x³(1-y)

Answer 1

a/ \(x^2-2x-15\)

\(=x^2+3x-5x-15\)

\(=x\left(x+3\right)-5\left(x+3\right)\)

\(=\left(x+3\right)\left(x-5\right)\)

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b/ \(y\left(x-z\right)+7\left(z-x\right)\)

\(=y\left(x-z\right)-7\left(x-z\right)\)

\(=\left(x-z\right)\left(y-7\right)\)

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c/ \(27x^2\left(y-1\right)-9x^3\left(1-y\right)\)

\(=27x^2\left(y-1\right)+9x^3\left(y-1\right)\)

\(=9x^2\left(y-1\right)\left(x+3\right)\)

Vậy...