Question

10+3/a=5^a

Answer 1

Taking log on both sides of base 5 probably helps is what I did ..

Answer 2

Taking natural log on both sides:
\[\ln{10} + \ln{\frac3a} = \ln{5^a}\]\[\ln10 + \ln3 - \ln a = a \times \ln 5 \]Differentiating both sides, we have:
\[0 + 0 - 1 / a = \ln 5\]\[a=-\frac{1}{\ln5}\]