Question 88226
1. {{{x^4-16}}}
Use difference of squares
{{{(x^2+4)(x^2-4)}}}
Can be factored further by using difference of squares
Answer is...
{{{(x^2+4)(x+2)(x-2)}}}
2. {{{3x^2-12y^2}}}
First, factor out the common factor of 3
{{{3(x^2-4y^2)}}}
Then use difference of squares to arrive at answer
{{{3(x-2y)(x+2y)}}}

Good luck!