[tex]\\ \sf\longmapsto E=mc^2[/tex]
[tex]\\ \sf\longmapsto c^2=\dfrac{E}{m}[/tex]
[tex]\\ \sf\longmapsto c=\sqrt{\dfrac{E}{m}}[/tex]
[tex]\\ \sf\longmapsto c=\dfrac{\sqrt{E}}{\sqrt{m}}[/tex]
Hence solved
