#### Answer

$(h\leq 42)$ U $(h\geq 58)$

#### Work Step by Step

To solve this, we must evaluate both parts: $$|\frac{h-50}{5}| \geq 1.645$$ becomes $\frac{h-50}{5} \geq 1.645$ and $\frac{h-50}{5} \leq -1.645$. Solving the first one results in: $$\frac{h-50}{5} \geq 1.645$$ $$h-50 \geq 8.225$$ $$h \geq 58.225$$ Solving the second one results in: $$\frac{h-50}{5} \leq -1.645$$ $$h-50 \leq -8.225$$ $$h \leq 41.775$$ This means that, in order for the coin to be considered $unfair$, the coin tosses should result in $58.225 \approx 58$ heads or more, or they should result in $41.775 \approx 42$ heads or less.