Theorem 1
Tag 06AW, permanent. Cite it as [Bourbaki, Tag 06AW].
Algebra, IV, p. 16, § 2. Zeros of polynomials
Let be an integral domain. Given a non-zero element of , of degree , then the sum of the orders of all the roots off in is .
This follows immediately from Prop. 5.
Bourbaki puts the proof directly after the statement, so what is above is the statement and its proof together.