Question

please help

Answer 1

54

Answer 2

how did u do that though?

Answer 3

foiling

Answer 4

http://en.wikipedia.org/wiki/FOIL_method

Answer 5

(a + b)(a - b) is the form of your expression.

You have to multiply that out:
a(a - b) + b(a - b) = a^2 - ab + ab - b^2 = a^2 - b^2

Answer 6

thanks

Answer 7

In this case, a is 8 and b is sqrt(10)