Question

Phân tích đa thức sau thành nhân tử: 15x²-2x-1

Answer 1

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

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

\(=\left(4x+x+1\right)\left(4x-x-1\right)\)

\(=\left(5x+1\right)\left(3x-1\right)\)

Answer 2

15x²-2x-1

=15x²-5x+3x-1

=(15x²-5x)+(3x-1)

=5x(3x-1)+(3x-1)

=(5x+1)(3x-1)