what is (f-g) (x)?
f(x) = 3x^5 +6x^2-5
g(x)=2x^4+7x^2-x+16
so (f-g) (x) = ?
(f - g)(x) means
f(x) - g(x) =
[ 3x^5 + 6x^2 - 5 ] - [ 2x^4 + 7x^2 - x + 16 ] =
3x^5 + 6x^2 - 5 - 2x^4 - 7x^2 + x - 16 =
3x^5 - 2x^4 - x^2 + x - 21
+155 
