Question 404648
(2x-4y)(2x+4y)
The slow way to multiply this is with FOIL. The faster way is to recognize that this expression fits the pattern {{{(a+b)(a-b) = a^2-b^2}}} with the "a" being 2x and the "b" being 4y. Using this pattern:
{{{(2x-4y)(2x+4y) = (2x)^2 - (4y)^2 = 4x^2 - 16y^2}}}<br>
FOIL should give you the same answer but after more work.