Please help i am very confused

Answer:
[tex]\sqrt{80}[/tex]
80 is the number in the square root
Step-by-step explanation:
[tex]d = \sqrt{(x_{2}-x_{1} )^{2} +(y_{2}-y_{1} )^{2} } \\d = \sqrt{(4-(-4) )^{2} +(5- 1 )^{2} }\\d = \sqrt{(4+4 )^{2} +4^{2}\\d = \sqrt{8^{2} +4^{2} }\\d=\sqrt{64 +16}\\d=\sqrt{80}[/tex]