Complete the following table of products of two monomials:

Add:

(i) 5a + 3b, a – 2b and 3a + 5b;

(ii) x³ – x²y + 5xy² + y, –x³ – 9xy² + y, and 3x²y + 9xy².

Subtract:

(i) –2xy + 3xy² from 8xy;

(ii) a – b – 2c from 4a + 6b – 2c.

Find the products:

(i) (5x + 8)3x

(ii) (–3pq) (–15p³q² – q³)

(iii) (3a³ – 3b³)

(iv) –x²(x – 15).

Simplify the following:

(i) (2xy – xy)(3xy – 5)

(ii) (3xy² + 1)(4xy – 6xy²)

(iii) (3x² + 2x)(2x² + 3)

(iv) (2m³ + 3m)(5m – 1).