Central Board Of Secondary Education – ( CBSE )
Class – 9
Subject Wise Courses For Class – 9
Mathematics For Class 9
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Recommended Question & Answers for Class 9
1. Find the zero of the polynomial in each of the following cases
(ii) p (x) = x – 5
Answer:
(i) We have, p(x) = x + 5. Since, p(x) = 0
⇒ x + 5 = 0
⇒ x = -5.
Thus, zero of x + 5 is -5.
(ii) We have, p(x) = x – 5.
Since, p(x) = 0 ⇒ x – 5 = 0 ⇒ x = -5
Thus, zero of x – 5 is 5.
2. Suppose you and your friend are on the moon. Will you be able to hear any-sound produced by your friend ?
No, I will not be able to hear sound, because moon has no atmosphere. Therefore, no sound waves can travel to your ears and, therefore, no sound is heard.
3. Explain the following giving examples:
(b) Suspension
Answer:
(a) Colloid: A colloid is a solution in which the size of solute particles are bigger than that of true solution. These particles cannot be seen with our naked eyes, they are stable, e.g., ink, blood.
(b) Suspension: It is a heterogeneous mixture in which the solute particles are big enough to settle down, e.g., chalk-water, paints, etc.