so that $H_0$ is equidistant from $H_1$ and $H_2$.
However, here the variable $\delta$ is not necessary. So we can set $\delta=1$ to simplify the problem.
$$w\cdot x+b=1 $$ and
$$w\cdot x+b=−1$$
Why is this assumption is taken? If it is taken, we can get the distance between two planes as $2$ directly because both are parallel and differ by $2$. how it is $\frac{2}{\left\|w\right\|}$ instead.
got equations from this https://www.svm-tutorial.com/2015/06/svm-understanding-math-part-3/