We can solve each system of equations separately to find the solution.
For the first system:
4x + y = -1
x + y = 2
Subtracting the second equation from the first equation gives:
3x = -3
x = -1
Substituting x = -1 into the second equation gives:
-1 + y = 2
y = 3
So the solution to the first system is x = -1 and y = 3.
For the second system:
8x + 2y = -2
-4x + cy = -8
Multiplying the second equation by 2 to make the coefficients of y the same gives:
-8x + 2cy = -16
Adding the two equations together gives:
8x - 8x + 2y + 2cy = -2 - 16
2y + 2cy = -18
Factoring out a 2 gives:
2(y + cy) = -18
Simplifying gives:
y + cy = -9
To have the same solution as the first system, we want y to be 3. So we can substitute y = 3 into the equation:
3 + 3c = -9
3c = -12
c = -4
Therefore, the value of c that would give the same solution for both systems is -4.