Question

Phân tích đa thức thành nhân tử:

x²+8x-2

Answer 1

x²+8x-2=x²+2.4.x+4²-4²-2=(x+4)²-18=(x+4)²-(3\(\sqrt{2}\))² = (x+4-3\(\sqrt{2}\))(x+4+3\(\sqrt{2}\))

Answer 2

\(x^2+8x-2\)

\(=x^2+8x+16-18\)

\(=\left(x^2+8x+16\right)-18\)

\(=\left(x+4\right)^2-\left(\sqrt{18}\right)^2\)

\(=\left(x+4-\sqrt{18}\right)\left(x+4+\sqrt{18}\right)\)