i got √50 but its wrong

Solve for http://gauss.vaniercollege.qc.ca/web...dd0b8b8e91.png:

http://gauss.vaniercollege.qc.ca/web...dd0b8b8e91.png equals

b) Solve for http://gauss.vaniercollege.qc.ca/web...dd0b8b8e91.png: http://gauss.vaniercollege.qc.ca/web...dd0b8b8e91.png equals