A factors with negative sign in the product with negative sign
If the product with negative sign has a factor with negative sign, then the negative sign of the product cancels out the negative sign of the factor.
If the product with negative sign has a factor with negative sign, then the negative sign of the product cancels out the negative sign of the factor.
If the product with negative sign has a factor with negative sign, then the negative sign of the product cancels out the negative sign of the factor.