Answer:=-36
Step-by-step explanation:
Answer: After 7 years the number of birds of species A and B are same. and the number of birds during that year will be 140.
Step-by-step explanation:
Given: Sharon is conducting research on two species of birds at a bird sanctuary.
The number of birds of species A is represented by the equation below,where S represents the number of birds, x years after beginning her research.

The number of birds of species B is represented by the equation below,where S represents the number of birds, x years after beginning her research.

To plot the above function, first find points by which they are passing.
For species A, At x=0 , 
At x=2 , 
Similarly find more points and plot curve on graph.
For species A, At x=0 , 
At x=2 , 
Plot a line with the help of these two points.
Now, from the graph the intersection of curve (for A) and line (for B) is at (7,140) which tells that After 7 years the number of birds of species A and B are same. and the number of birds during that year will be 140.
There is actually 2 ways to solve this, I will show you both.
The first is obvious, solve for x in the first one, and plug it into the 2nd one and get the answer
4x + 7 = 12
4x = 5
x = 
8(
) + 3
2 * 5 + 3
10 + 3
13
The 2nd option is to manipulate the 4x + 7 to be 8x + 3
4x + 7 = 12
start by moving the 7 over
4x = 5
multiply both sides by 2
8x = 10
and add 3 to both sides
8x + 3 = 13
Should be A I’ll show you what I did though it might not make sense because I kind of did it in a weird way but yeah that answer should be A hope this helps :)