Find each of the following products:
(3x2 + 5x - 9) × (3x – 5)
By using horizontal method,
We have;
= (3x2 + 5x – 9) × (3x – 5)
= 3x(3x2 + 5x – 9) – 5(3x2 + 5x – 9)
= 9x3 + 15x2 – 27x – 15x2 - 25x + 45
By arranging the expression in the form of descending powers of x,
We get;
= 9x3 + 15x2 – 15x2 – 27x – 25x + 45
= 9x3 – 52x + 45