Evaluation the following:

A.
[tex] \sqrt{ \frac{32 {y}^{2} }{72 {x}^{2} } } [/tex]
B.
[tex] \sqrt[3]{ \frac{125 {m}^{3} }{36 {m}^{2} } } [/tex]
C. if
[tex] x1 = 2 \: and \: x2 = 1 \\ and \: y1 = 3 \: and \: y2 = - 1[/tex]
then find the value of :
[tex] \sqrt{ \frac{x2}{y2} - \frac{y2}{x2} } [/tex]