Question 34358
you would foil that

(4x+3w^2)(4x-3w^2)
 4x*4x=16x^2
 4x*- 3w^2= -12w^2x
 3w^2*4x= 12w^2x
 3w^2*- 3w^2= -9w^4

so...
your first awnser is 
 16x^2-12w^2x+12w^2x-9w^4

then collect like terms to get the final awnser
16x^2+w^4x^2-9w^4