Which is the smallest among $2^{50},\ 3^{40},\ 5^{30}$?
Which is the smallest among $2^{50},\ 3^{40},\ 5^{30}$?
$2^{50}$
$3^{40}$
$5^{30}$
All equal
Solution
Bring to common index 10: $2^{50} = 32^{10}$, $3^{40} = 81^{10}$, $5^{30} = 125^{10}$. Smallest base $\Rightarrow$ smallest number, so $2^{50}$ is smallest.