Help me? Product of a sum and a difference
Formula; (a + b)(a - b) = a^2 - b^2
Find the product of the following
1. (2x - 5)(2x + 5)
2. (5b - 6y)(5b + 6y)
3. (4k + 7)(4k - 7)
4. (y - 5)(y + 5)
5. (3x - 2)(3x + 2)
6. (13x + 2x^3)(13x - 2x^3)
7. (2a + 1)(2a - 1)
8. (9y^2 + 8)(9y^2 - 8)