Respuesta :

We're adding n and m onto k to get P. Undo these operations to isolate k. So we subtract m from both sides

P = k+n+m

P-m = k+n+m-m

P-m = k+n

and we subtract n from both sides

P-m = k+n

P-m-n = k+n-n

P-m-n = k

k = P-m-n  is the final answer