Indian Certificate Of Secondary Education – ( ICSE )

Recommended Question & Answers for Class 9

1.What is Sublimation ?

The process by which a solid directly change to its vapor state or gaseous state without passing through liquid state and vice versa is called sublimation.

2. What is melting ?

It is a process of change of state of a substance from gaseous state to liquid state at particular temperature, it is also known as condensation.

3. What are vaccines?

Vaccines are materials administered in the body to provide passive immunity . the materials are generally germs or substance secreted by germ.

4. Prove that if a+b+c, then solve a³ + b³ + c³ = 3abc. The given value of a = -10, b = -6 and c = – 4.

a + b + c = 0
By substituting the value of a, b and c, we obtain a + b + c = 0
⇒ -10 + 6 + 4 = 0
0 = 0
a³ + b³ + c³ = 3abc

By substituting the value of a, b and c, we obtain a3 + b3 + c3 = 3abc
(-10)³ + (6)³ + (4)³ = 3 (-10)(6)(4)
-1000 + 216 + 64 = -720
-720= -720
So, if a + b + c = 0, then a³ + b³ + c³ = 3abc.