I am assuming you meant to write the following options
A. f(x)=x+3; g(x)=√x
B. f(x)=x; g(x)=x+3
C. f(x)=√x; g(x)=x+3
D. f(x)=3x; g(x)=√x
You need to find a fucntion f(x) that once evaluated in g(x) gives us as a result h(x)
h(x) = g(f(x))
Looking at the options, the answer is A.
g(f(x)) = sqrt(f(x)) = sqrt (x + 3) = h(x)
Answer:
The value of x = -1 makes the denominator of the function equal to zero. That is why this value is not included in the domain of f(x)
Step-by-step explanation:
We have the following expression

Since the division between zero is not defined then the function f(x) can not include the values of x that make the denominator of the function zero.
Now we search that values of x make 0 the denominator factoring the polynomial 
We need two numbers that when adding them get as a result -1 and when multiplying those numbers, obtain -2 as a result.
These numbers are -2 and 1
Then the factors are:

We do the same with the numerator

We need two numbers that when adding them get as a result 4 and when multiplying those numbers, obtain 3 as a result.
These numbers are 3 and 1
Then the factors are:

Therefore

Note that
only if 
So since
is not included in the domain the function has a discontinuity in 
The formula of the perimeter of a rectangle is 2l+2w so look at the photo
For the first one it might be 26? i’m not so sure