Câu trả lời:

\(\left(x+3\right)\left(x^2-5x-2\right)\)

\(=x^3-5x^2-2x+3x^2-15x-6\)

\(=x^3-\left(5x^2-3x^2\right)-\left(2x+15x\right)-6\)

\(=x^3-2x^2-17x-6\)