Write an expression with (-1) as its base that will produce a positive product

The expression with '-1' as its base that will produce a positive product is

, where n is a natural number.

If we take n=1, we get which is positive.

If we take n=2, we get which is also positive.

Similarly if we take any natural number in this expression, it will give a positive product.

Hence, is the required expression.

square pyramid

step-by-step explanation:

square prism looks like nothing like that

triangular prism has a rectangular base instead of a square base

tetrahedron has a triangular base