Hint for Section G.2 Question 2

2. We must show that for all x,y Î H, x × y^-1 Î H.

We begin by noting that if x,y Î H, then x² = e and y² = e.
Thus x = x^-1 and y = y^-1.

Now to show that x × y^-1 Î H we must show (x × y^-1)² = e.

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