These formulas can be used.
I will learn many formulas in the future.
You can also use it.
Mathematics in the college entrance examination is not about whether this formula can be used, but about logic.
Update 1: Not every copy must be the same.
That means: cut one knife: 2+2 cut two knives: 4+4 cut three knives: 8+6 cut four knives: 14+8 cut five knives: 22+ 1