2x – y = –2
x = 14 + 2y

what is the value of the system determinant?
what is the value of the y−determinant?
what is the value of the x−determinant?
what is the solution to the system of equations?

There is 3 different ways you can approach this question, I´ll do it by using the substitution method.
1. Solve for y in 2x-y=-2
2x-y=-2
-y=-2-2x
y=2+2x

2. Substitute y=2+2x into x=14+2y
x=14+2y
x=14+2(2+2x)
x=4x+18

3. Solve for x in x=4x+18
x=4x+18
x-4x=18
-3=18
x=-18/3
x=-6

4. Substitute x=-6 into y=2+2x
y=2+2x
y=2+2*-6
y=-10

5. Therefore, 
x=-6
y=-10

2x- y = -2

x - 2y = 14

x = 18/-3 = -6, y = 30/-3 = -10

D+=matrix%282%2C2%2C2%2C-1%2C1%2C-2%29 = -3

D%5By%5D+=matrix%282%2C2%2C2%2C-2%2C1%2C14%29 = 30

D%5Bx%5D+=matrix%282%2C2%2C-2%2C-1%2C14%2C-2%29 = 18