What expressions are equivalent to (a^2-16)(a+4)

Ammonia molecules have three hydrogen atoms and one nitrogen atom.how many of each atom arein five molecules of ammonia

What is the absolute value of the complex number -4-sqrt2i

Write each of the following numerals in base 10. for base twelve, t and e represent the face values ten and eleven, respectively. 114 base 5 89t base 12