Question

va roog mult.... e urgent

Answer 1

[tex]f=20\ cm=0,2\ m\\ x_1=-30\ cm=-0,3\ m\\ \dfrac{1}{x_2}-\dfrac{1}{x_1}=\dfrac{1}{f}\\ \dfrac{1}{x_2}=\dfrac{1}{f}+\dfrac{1}{x_1}\\ \dfrac{1}{x_2}=\dfrac{x_1+f}{f\cdot x_1}\\ x_2=\dfrac{f\cdot x_1}{x_1+f}\\ x_2=\dfrac{0,2\cdot (-0,3)}{-0,3+0,2}=\dfrac{-0,06}{-0,1}=0,6 m=60\ cm\\ \text{Raspunsul este a)}.[/tex]