P + nx=rx-e (solve for x)

(p+e) / (r-n) = x

Step-by-step explanation:

p + nx=rx-e

Add e to each side

p + e + nx=rx-e+e

p + e + nx=rx

Subtract nx from each side

p + e + nx - nx=rx-nx

p+e = rx - nx

Factor out x

p+e = x (r-n)

Divide each side by (r-n)

(p+e) / (r-n) = x (r-n) / (r-n)

(p+e) / (r-n) = x