We take the 2 terms of the first bracket and multiply both of them by the second bracket.

(2x + 3)(x²− x − 5)

= (2x)(x² − x − 5) + (3)(x² − x − 5)

= (2x³ − 2x² − 10x) + (3x² − 3x − 15)

= 2x³ + x² − 13x − 15

This time we could collect together some like terms. There was:

-2x² + 3x² = x²

and

-10x − 3x = -13x