k=1/2mv^2, for m

Question

V= h/e v- E/e, for e

Please help.

Answer 1

k=1/2mv^2
2k = mv^2
m = 2k/v^2

your second equation is not clear.
Why is there a space between the e and v ?

I will assume it is
V = (h/e)v - E/e , then
eV = hv - E
e = (hv - E)/V