4n^2-16 factor the quadratic

(2n+4)(2n-4)
This way when you distribute it out, you get 4n^2-8n+8n-16.
Then the -8n and the 8n cancel out and you are left with 4n^2-16.
Another way of factoring it is to start out by taking out a common factor which is 4.
This then becomes 4(n^2-4) You can then factor that by using the method above into 4(n+2)(n-2).
The second way is just a bit more factored but they're both an answer.

x = 1 , y = 8  thus: A. is your answer

Step-by-step explanation using substitution:

Solve the following system:

{y = 2 x + 6

y = 11 - 3 x

Hint: | Perform a substitution.

Substitute y = 2 x + 6 into the second equation:

{y = 2 x + 6

2 x + 6 = 11 - 3 x

Hint: | Choose an equation and a variable to solve for.

In the second equation, look to solve for x:

{y = 2 x + 6

2 x + 6 = 11 - 3 x

Hint: | Isolate x to the left hand side.

Subtract 6 - 3 x from both sides:

{y = 2 x + 6

5 x = 5

Hint: | Solve for x.

Divide both sides by 5:

{y = 2 x + 6

x = 1

Hint: | Perform a back substitution.

Substitute x = 1 into the first equation:

{y = 8

x = 1

Hint: | Sort results.

Collect results in alphabetical order:

{x = 1 , y = 8