The subtraction property of inequalities states that if the same number is subtracted from each side of a true inequality, the resulting inequality is also true that is:
(i) If , then .
(ii) If , then .
The multiplication property of inequalities states that if both sides of the inequality are multiplied by a positive number the sign of the inequality remains the same and if both sides of the inequality are multiplied by a negative number then the sign of the inequality changes that is:
(i) If and role="math" localid="1647496591700" is a positive number then .
(ii) If andis a positive number then .
(ii) If and is a negative number then .
(iv) If and is a negative number then .