In the Check Your Learning section of Example $27.1,$ you were told that several lines of hydrogen absorption in the visible spectrum have rest wavelengths of $410 \mathrm{nm}, 434 \mathrm{nm}, 486 \mathrm{nm},$ and $656 \mathrm{nm} .$ In a spectrum of a distant galaxy, these same lines are observed to have wavelengths of $492 \mathrm{nm}, 521 \mathrm{nm}, 583$ nm, and 787 nm, respectively. The example demonstrated that $z=0.20$ for the 410 nm line. Show that you will obtain the same redshift regardless of which absorption line you measure.