In a sentence, explain whether the galaxy exhibits a redshift or a blueshift?

Question

A certain spectral line of hydrogen gas has a wavelength of 434.2 nm when measured in the laboratory. In the spectrum of a particular distant galaxy, this same spectral line has a wavelength of 455.9 nm.

In order to demonstrate the learning outcomes fully in this question you must show all your working throughout.

Answer 1

If it is a blueshift the wavelengths get ???? and as frequency = c/wavelength the frequencies get ?????

do the wavelengths get longer or shorter?