Ok Im having trouble understanding part 2 and 3 of this question.
Q. State the value of A for which the graph of y=f(x) has a line of symmetry.
What does it mean exactly...?
And Im looking for a quick explanation on how to find the range and domain for any type of question.
Cheers if some1 can explain the above 
When you bring down a function (equation) in the completed square form, you will get the answer in the form : a (x + b)
2 + c
So the
b which you get is the line of the symmetry.
For example if you got the square form as : a(x+b)
2 + c, then :
x = -b is your line of symmetry. Note if c is negative, the symmetry is
c = -(-b), making it
x = b.
DOMAIN AND RANGE :
Normally, in a question about functions, you will be given EITHER domain (the values which x can take) of the function OR range (the value of the whole function) OR both.
You have normal function, you find it's range if domain is given or either way, or if both are given, take it !
Then you find it's inverse, so :
The range of inverse function will be achieved by placing the values of x from domain of the normal function.
The domain will be achieved by placing the values of x from range of the normal function.
