Question

Please help, will medal
Why are the following expressions not monomials?

3cd^x
- The variable is in the denominator
-The exponent is not a non-negative integer
- The expression is not a product

x+2w
- The variable is in the denominator
-The exponent is not a non-negative integer
- The expression is not a product <-- for this one I believe its this answer


3/h
- The variable is in the denominator
-The exponent is not a non-negative integer <-- I think maybe this one for this
- The expression is not a product

ab^-1
- The variable is in the denominator
-The exponent is not a non-negative integer
- The expression is not a product