To find the value of (a+b), we need to evaluate the function f(x) and substitute the given values f(0) = a and f(4) = b.
Let's start by dividing the function f(x+3) by (x^2+2x-3) and finding the quotient Q(x) and remainder (x+2).
To divide f(x+3) by (x^2+2x-3), we can do the following steps:
Step 1: Rewrite f(x+3) as f(x) by substituting x+3 with x in the function f(x+3).
Step 2: Perform long division using f(x) and (x^2+2x-3).
Step 3: Write the quotient as Q(x) and the remainder as (x+2).
Now let's evaluate the function f(x) using the given values f(0) = a and f(4) = b.
Step 4: Substitute x = 0 in Q(x) and add the remainder (x+2). This gives us the value of f(0).
Step 5: Substitute x = 4 in Q(x) and add the remainder (x+2). This gives us the value of f(4).
Finally, we can calculate (a+b) by adding the values of f(0) and f(4).
Since the options provided do not give the actual numerical values of (a+b), we cannot directly determine the answer (a+b) from the given options. We would need to go through the steps described above to find the value of (a+b) based on the specific function f(x+3) and the values of f(0) and f(4) that are not given in the question.