W1:A1:Excercise 3: operands could not be broadcast together with shapes (3,2,4) (3,3,4)

I dont know what I am doing wrong. I have attached the error snippet

The error means that there is something wrong with the multiplication, check the shapes of a_slice_prev and W, they are not as suposed to be to achieve the multiplication operation (keep in mind these are vectors).

Thank you for the answer. Seems like I had parentheses mistake for n_H and n_W formula

what you mean by it?

I mean their shapes are not right to multiply them.