Question 625271
One could just use FOIL to multiply this. But it's faster if you realize that
{{{(x^2 + 4)(x^2 - 4)}}}
exactly matches the pattern of the left side of
{{{(a+b)(a-b) = a^2-b^2}}}
with the "a" replaced by {{{x^2}}} and the "b" being replaced by "4". So, according to the right side of the pattern, the product will be:
{{{(x^2)^2-(4)^2}}}
which simplifies to:
{{{x^4-16}}}<br>
P.S. You get the same answer if you use FOIL correctly.