It’s b. :) hope this helps you
Answer:
There are two possibilities:
and 
and 
Step-by-step explanation:
Mathematically speaking, the statement is equivalent to this 2-variable non-linear system:


First,
is cleared in the first equation:

Now, the variable is substituted in the second one:

And some algebra is done in order to simplify the expression:


Roots are found by means of the General Equation for Second-Order Polynomials:
and 
There are two different values for
:






There are two possibilities:
and 
and 
(f∘g)(x) is equivalent to f(g(x)). We solve this problem just as we solve f(x). But since it asks us to find out f(g(x)), in f(x), each time we encounter x, we replace it with g(x).
In the above problem, f(x)=x+3.
Therefore, f(g(x))=g(x)+3.
⇒(f∘g)(x)=2x−7+3
⇒(f∘g)(x)=2x−4
Basically, write the g(x) equation where you see the x in the f(x) equation.
f∘g(x)=(g(x))+3 Replace g(x) with the equation
f∘g(x)=(2x−7)+3
f∘g(x)=2x−7+3 we just took away the parentheses
f∘g(x)=2x−4 Because the −7+3=4
This is it
g∘f(x) would be the other way around
g∘f(x)=2(x+3)−7
now you have to multiply what is inside parentheses by 2 because thats whats directly in front of them.
g∘f(x)=2x+6−7
Next, +6−7=−1
g∘f(x)=2x−1
Its a lts easier than you think!
Hope this helped