1) Expand and Simplify

(4x-3)(x+5)

2) Prove that

(n+5)^2 - (n+3)^2 = 4(n+4)

3)

a) Expand and simplify (2n+1)^2

b) Prove that the square of any odd number is always 1 more than a multiple of 8.

4) Expand and simplify (x-3)(2x+1)

5)

a) Expand and simplify (x+y)(x-y)

b) Using your answer to part (a). or otherwise, find the exact value of

780^2 - 220^2