Let f(x)=x^1999 and g(x)=2x-x^5. Then f(x)g(x) equals____?
A. 2x^20000-x^2004
B. 2x-x^5+x^1999
C. (2x-x^5)^1999
D. 2x^1999-x^9995
f(x)g(x)=
x^1999 * (2x - x^5)
note that to multiply terms with the same base (in this case, the base is the variable x), we just add their exponents:
2*x^(1999+1) - x^(1999+5)
2x^2000 - x^2004
if it's just a typo, the answer is A. :)