Solve 22 and 24 number.it is simple differentiation but tell me what is mean by f(x) and g(x) here and how solve it.i am very worried.?

Questions 22 and 24 are the basic properties of derivatives.

22 says that the derivative of a difference of 2 functions is the difference of the functions' derivatives

24 says that the derivative of a sum of 3 functions is the sum of the functions' derivatives.

In these questions #f(x)#, #g(x)# and #h(x)# are any functions whose derivative is defined

I think that you are asking about the notation #f(x)#.

We use this notation for a function.

One way to think about a function is simply as another name for #y#.

So instead of writing

#y = x^2+3#

We can write

#f(x) = x^2+3#
We read this "f of x equals x squared plus 3".
#f# is the name of the function and #f(x)# is a name for #y#.

Instead of writing:

If #y = x^2+3#, find #y# when #x = 2#

We can write

If #f(x) = x^2+3#, find #f(3)#
We read #f(3)# as "f of 3# and, since #(3)^2+3 = 9#, we say "f of 3 is [or equals] 9".

A function is like an operation performed on some input. It takes an input and gives an output. Some of the algebra operations and some calculator buttons are (simple) functions.

With #y = f(x)# we write #f'(x)# (read "f prime of x") for #dy/dx#

Instead of saying

Find #dy/dx# when #x = 5#

we can say

Find #f'(5)# ("find f prime of 5")

You can read more about functions at Socratic under the Subject: Algebra.
Use the Subject pull-down list above. Select Algebra.
Then when Algebra loads, select Topics. You can look for topics about functions.

On a personal note

Many students are now taught about functions when they learn algebra. The first time I saw a function or the word "function" was in my first calculus class.
For a long time I thought of functions as I have described them. #f(x) is another name for #y#.
There's more to it than that, but it gets you going in the right direction.

Question 22 could be rewritten as follows.

With #y = f(x)# and #z = g(x)#

what is #d/dx(y-z)#?

Answer (C.) #f'(x)-g'(x)# is the same as #dy/dx-(dz)/dx#