Exponents with the same power

I've wanted to practice solving simple operations on exponents, so I've made a couple of equations to which I know the answers.

${5}^{x}-{4}^{x}=9$

I feel really stupid, because I can't solve this one (obviously the answer is 2). I can't separate the x's after using logarithms.

Any hints? Thanks.

I've wanted to practice solving simple operations on exponents, so I've made a couple of equations to which I know the answers.

${5}^{x}-{4}^{x}=9$

I feel really stupid, because I can't solve this one (obviously the answer is 2). I can't separate the x's after using logarithms.

Any hints? Thanks.