make the subject (u) p=5t-u/u

This makes little sense to me.

-u/u reduces to -1, so u cannot be made the subject. Are there typos in your data?

To simplify the expression p = (5t - u) / u and make the subject "u," we want to isolate "u" on one side of the equation. Here's the step-by-step solution:

1. Start with the given equation: p = (5t - u) / u.

2. Multiply both sides of the equation by "u" to eliminate the denominator:
p * u = 5t - u.

3. Distribute "u" to both terms within the parentheses:
p * u = 5t - u.

4. Move the term "-u" to the left side of the equation by adding it to both sides:
p * u + u = 5t - u + u.

Simplify:
p * u + u = 5t.

5. Combine "u" terms on the left side of the equation:
u * (p + 1) = 5t.

6. Finally, divide both sides of the equation by (p + 1) to solve for "u":
u = (5t) / (p + 1).

So, the expression "u" in terms of "t" and "p" is given by u = (5t) / (p + 1).