There are 3 ways of solving a simultaneous problem, substitution method, elimination method and Gauss-Jordan method. I'm gonna use the substitution method since it's easier and i think it would suit your level more.
First let's try solving for y since it's easier to start with.
Firstly we have to find an equation for x:

Great, now we can use the substitution method to find the value of y using the first equation:

Now we know that y=1 we can solve the first equation we made:

And the answer is 
Double check:

And that's our final answer! (4,1)
-2.5(1-2n)-1.5n
=-2.5+5n-1.5n
=-2.5+3.5n
Answer: B. -2.5+3.5n
No this is not a function because 4 is used twice on the y side
Answer:
5.381
Step-by-step explanation: