Asubstance that is made up of only one kind of atom is a(an)
a. compound.
b. homogeneous mixture.
c. element.
d. solution.

it is a element

That is the answer :)

hello from mrbilldoesmath!

answer:

x - 3

discussion:

x^2 - 9 = (x-3) (x+3)   so

(x^2-9)/ (x + 3) = x-3

you,

mrb