I'm a beginner in commutative algebra, and I'm self-studying this subject via R.Y. Sharp's textbook.
Let $R$ be a commutative ring with $1$ which contains an infinite field as a subring. Let $I$ and $J_1,\ldots,J_n$ where $n\ge2 $, be ideals of $R$ such that:
$$I\subseteq J_1\cup J_2\cup\cdots\cup J_n.$$
Prove that $I \subseteq J_j$ for some $j$ with $1\le j \le n$.
It looks similar to the Prime Avoidance Theorem, but in this case each $J_i$ just to be ideals and I can't figure out what the role of "contains an infinite field as a subring" in this situation.
I expect for some idea / suggestion. Thank in advance.