Hahn Banach theorem for normed spaces

$\textbf{Hahn Banach theorem for normed spaces}$ Let $U$ be a subspace of a normed space $X$. For every bounded linear functional $u^*:U\to\mathbb{F}$ there exists a bounded linear functional $x^*:X\to\mathbb{F}$ such that $\lVert x^*\rVert=\lVert u^*\rVert$ and the restriction of $x^*$ to $U$ is $u^*$. That is, $u^*$ can be extended to a bounded linear functional on $X$ having the same norm.
$\textbf{Hahn Banach theorem for normed spaces}$ Let $U$ be a subspace of a normed space $X$. For every bounded linear functional $u^*:U\to\mathbb{F}$ there exists a bounded linear functional $x^*:X\to\mathbb{F}$ such that $\lVert x^*\rVert=\lVert u^*\rVert$ and the restriction of $x^*$ to $U$ is $u^*$. That is, $u^*$ can be extended to a bounded linear functional on $X$ having the same norm.
copied
๐‡๐š๐ก๐งย ๐๐š๐ง๐š๐œ๐กย ๐ญ๐ก๐ž๐จ๐ซ๐ž๐ฆย ๐Ÿ๐จ๐ซย ๐ง๐จ๐ซ๐ฆ๐ž๐ย ๐ฌ๐ฉ๐š๐œ๐ž๐ฌ Let ๐‘ˆ be a subspace of a normed space ๐‘‹. For every bounded linear functional ๐‘ข*:๐‘ˆโ†’๐”ฝ there exists a bounded linear functional ๐‘ฅ*:๐‘‹โ†’๐”ฝ such that โˆฅ๐‘ฅ*โˆฅ=โˆฅ๐‘ข*โˆฅ and the restriction of ๐‘ฅ* to ๐‘ˆ is ๐‘ข*. That is, ๐‘ข* can be extended to a bounded linear functional on ๐‘‹ having the same norm.
copied