Page 47 - Mathematics Class - XI

Viva-Voce

1. What is meant by inequality?
Ans. Two real numbers or two algebraic expressions related by the symbol ‘<’, ‘>’, ‘≤’ or ‘≥’ form an inequality.

2. What do you mean by the solutions of an inequality?
Ans. The values of variables, which make an inequality a true statement, are called solutions of the inequality.
3. What is meant by solution set?

Ans. The set of all possible solutions of an inequality is known as its solution set.
4. State which of the following statements is True or False.

x y
(i) If x < y and b < 0, then <
b b
(ii) If xy > 0, then x < 0 and y < 0

Ans. (i) False (ii) True

5. What do you understand by strict and slack inequalities?
Ans. Inequalities involving the symbol ‘>’ or ‘<’ are called strict inequalities and inequalities involving the
symbol ‘≥’ or ‘≤’ are called slack inequalities.

MCQs

1. The solution of the inequality x – 4x < 12 then
2
a) x < –2 or x > 6 b) –6 < x < 2 c) 2 < x < 6 d) –2 < x < 6

2. If the inequality is x + 2ax + 10 – 3a > 0 and x∈R, then
2
a) –5 < a < 2 b) a < –5 c) a > 5 d) 2 < a < 5
3. If x < 5, then

a) –x < –5 b) –x < –5 c) –x > –5 d) –x > –5
4. Given that x, y, b are the real numbers and x < y, b < 0, then
x y x y x y x y
a) < b) ≤ c) > d) >
b b b b b b b b
5. If |x + 2| < 9, then

a) x∈(–7, 11) b) x∈[–11, 7]
c) x∈(–∞, –7) ∪ (11, ∞) d) x∈(–∞, –7) ∪ [11, ∞)

Answers: 1. d) –2 < x < 6 2. a) –5 < a < 2 3. c) –x > –5

4. c) x > y 5. b) x∈[–11, 7]
b b

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