What two important discoveries did daguerre make?

On January 7, 1839, members of the French Académie des Sciences were shown products of an invention that would forever change the nature of visual representation: photography. The astonishingly precise pictures they saw were the work of Louis-Jacques-Mandé Daguerre (1787–1851), a Romantic painter and printmaker most famous until then as the proprietor of the Diorama, a popular Parisian spectacle featuring theatrical painting and lighting effects. Each daguerreotype (as Daguerre dubbed his invention) was a one-of-a-kind image on a highly polished, silver-plated sheet of copper.

6.58-8.36x=3.98x-27.33

Collecting like terms

6.58+27.33=3.98x+8.36x

33.91=12.34x

33.91/12.34=12.34/12.34

x=2.75