# Prove it!

Level pending

In which step does the following proof go wrong? Or is this a valid proof?

1. $$a = b$$
2. $$\ln a = \ln b$$
3. $$\dfrac{\ln a}{\ln b} = 1$$
4. $$\ln a - \ln b = 0$$
5. $$\ln\left(\dfrac{a}{b}\right)= 0$$
6. $$\dfrac{a}{b} = 1$$
7. When $$a = b = 0$$, $$\dfrac{-\infty}{-\infty} = \dfrac{0}{0} = 1$$
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