Tolong kk dibantu besok dikumpul

[tex] \frac{1}{f} = \frac{1}{s}+ \frac{1}{s'} \\ \frac{1}{20} = \frac{1}{30}+ \frac{1}{s'} \\ \frac{1}{20} - \frac{1}{30}= \frac{1}{s'} \\ \frac{3-2}{60} = \frac{1}{s'} \\ s'=60[/tex]
perbesaran = M
[tex]M= \frac{s'}{s} = \frac{60}{30} =2 kali[/tex]