When graphing inequalities on a number line, if you multiply by a negative, you have to change the sign to the opposite sign. For example, if an inequality is x/-4>4, and you multiply both sides by -4, the inequality becomes x<-1. However, if the inequality is x/4>-4, and you multiply both sides by 4, the inequality is x>-1, without using the opposite sign... but the communitive property of multiplication says -4 times 4 is the same as 4 times -4. Why does this not apply to inequalities?