Question

phân tích đa thức thành nhân tử 

4x^2-4x-y^2-8y-15

giúp mình với 

 

 

 

Answer 1

\(4x^2-4x-y^2-8y-15\)

\(=\left(4x^2-4x+1\right)-\left(y^2+8y+16\right)\)

\(=\left(2x-1\right)^2-\left(y+4\right)^2\)

\(=\left(2x+y+3\right)\left(2x-y-5\right)\)

Answer 2

\(4x^2-4x-y^2-8y-15\)

\(=\left(4x^2-4x-1\right)-\left(y^2-8y-16\right)\)

\(=\left(4x^2-4x-1\right)-\left(y^2+8y+16\right)\)

\(=\left[\left(2x\right)^2-4x-1\right]-\left[y\left(y+8\right)\right]+16\)

\(=\left(2x^2-6x\right)\left(y+12\right)\left(y-4\right)\)

...