I'm assuming that you mean

because if you meant

then u would simplify and you couldn't make it the subject.
Under this assumption, we start with

We multiply both sides by 

We expand the left hand side:

We move all terms involving u to the left and all terms not involving u to the right:

We factor u on the left hand side:

We divide both sides by 

No se pero me gustaría alludar
Heyy I don’t think your pictures are loading it just shows grey
The answer for number 4: Temperature is an average of average heat. Heat is the average kinetic energy and thermal energy is kinetic energy.
(I can't see the answer for number 10... it would be good if you told me the question)