Løs ulikheten ${3,5}^x>439$ $$\begin{array}{llllll}\hfill {3,5}^x& >439& \hfill & & \hfill & \\ \hfill \ln {3,5}^x& >\ln 439& \hfill & & \hfill & \\ \hfill x\ln 3,5& >\ln 439& \hfill & |:\ln 3,5& \hfill & & \hfill & \\ \hfill x& >\frac{\ln 439}{\ln 3,5}\approx 4,9& \hfill & & \hfill & \end{array}$$

Løs ulikheten $50\cdot {1,05}^x>300$ $$\begin{array}{llllllll}\hfill 50\cdot {1,05}^x& >300& \hfill & |:50& \hfill & & \hfill & \\ \hfill {1,05}^x& >6& \hfill & & \hfill & \\ \hfill \ln {1,05}^x& >\ln 6& \hfill & & \hfill & \\ \hfill x\ln 1,05& >\ln 6& \hfill & |:\ln 1,05& \hfill & & \hfill & \\ \hfill x& >\frac{\ln 6}{\ln 1,05}\approx 36,7& \hfill & & \hfill & \end{array}$$

Løs ulikheten $3\cdot {0,25}^x>27$ $$\begin{array}{llllllll}\hfill 3\cdot {0,25}^x& >27& \hfill & |:3& \hfill & & \hfill & \\ \hfill {0,25}^x& >9& \hfill & & \hfill & \\ \hfill \lg {0,25}^x& >\lg 9& \hfill & & \hfill & \\ \hfill x\lg 0,25& >\lg 9& \hfill & |:\lg 0,25& \hfill & & \hfill & \\ \hfill x& <\frac{\lg 9}{\lg 0,25}\approx -1,6& \hfill & & \hfill & \end{array}$$