Compare between exponents

Question

which one will be larger,

$99^{99}-99^{98}$

or

$99^{98}$

I could not find any exponent properties that will help solving this.

Answer 1

You could use substitution. Let $99^{98}$ be $x$. Then the two choices would be $$99x-x$$ and $$x$$ Now you can obviously see that $99^{99}-99^{98}$ is larger.