umm...

9(4v*6v)=10(5v*5v)
9*(4v*6v)=10*(5v*5v)
9*(24v*v)=10*(25v*v)
9*(24v^2)=10*(25v^2)
9*24v^2=10*25v^2 | -10*25v^2
9*24v^2 - 10*25v^2 = 0
(9*24 - 10*25 )*v^2 = 0
-34v^2 = 0 | /-34
v^2 = 0/-34
v^2 = 0
v = +0 or v=-0

[input]9(4v*6v)=10(5v*5v)[/input]