Why won't my bow enchant?

I got an enchanted book with Fire Protection IV and Infinity I (in that order).

I went to my anvil and tried to add it to my bow that had Unbreaking III and Mending I and it had the x over the arrow that adds them together (which means I cannot merge them together in Minecraft) and I can't figure out why.

Can someone please explain how to fix this issue? Please and thank you.

Infinity and Mending will not combine, and fire protection cannot be applied to a weapon/tool.

Mending and Infinity are mutually exclusive.

Source

Normally, if you had a book that did have an enchantment that could be applied (eg. Flame), it would be applied regardless of other enchantments. The book would be consumed and only the applicable enchantments would be applied, the rest would be lost.