Posted by John on .
R=square root of u squared plus v squared divided by m and u and v are positive.Find u when r=3,v=6 and m=5

Maths 
bobpursley,
the problem with language is it imprecise. That is why the French Academy in the 1700's went to symbols.

Maths 
Steve,
R = √(u^2+v^2)/m
so, just plug in the numbers:
3 = √(u^2+6^2)/5
15 = √(u^2+36)
Now square both sides to get
u^2+36 = 225
u^2 = 189
u = ±√189 = ±3√21