By using horizontal method,

We have;

= (x² – 3x + 7) × (2x + 3)

= 2x(x² – 3x + 7) + 3(x² – 3x + 7)

= 2x³ - 6x² + 14x + 3x² – 9x + 21

By arranging the expression in the form of descending powers of x,

We get;

= 2x³ – 6x² + 3x² + 14x – 9x + 21

= 2x³ – 3x² + 5x + 21