Answer:
The answer is B: (1,2)
Step-by-step explanation:
(solved using elimination method)
-2x+y=0
y=x+1
-x+y=1
-2x+y=0
x+y=-1
-x=-1
x=1
-1+y=1
y=2
(x,y)=(1,2)
Since 4 is between 2 & 5 you input it into the middle equation.
x=4
so the answer is 4!
If

then

The ODE in terms of these series is



We can solve the recurrence exactly by substitution:


So the ODE has solution

which you may recognize as the power series of the exponential function. Then

Answer:
2*(x-5) = -33, so x-5 = -16.5, so x = -11.5
This is assuming that "the difference between a and b" is a-b, which seems to be the accepted interpretation.