Using standard formulae, expand each of the following:

(i) (x + 7)(x + 4)

(ii) (a + 13)(a - 8)

(iii) (y - 6)(y - 4)

Using standard formulae, expand each of the following:

(i) (9 + 2x)(9 - 3x)

(ii) (5x - 4y)(5x + 3y)

(iii) (3 - 7a)(3 + 4a)

Using standard formulae, expand each of the following:

(i) (2 - x)(2 + x)(4 + x²)

(ii) (x + y)(x - y)(x² + y²)

Using standard formulae, expand each of the following:

(i) (x - 2)(x - 3)(x + 4)

(ii) (x - 5)(2x - 1)(2x + 3)