18. If x, 1, z are in A. P. and x, 2, z are in G. P. then x, 4, z are in
1. G. P.
2. H. P.
3. A. P.
4. none​

50 plz, given the system of equations, match the following items. x + 3 y = 5 x - 3 y = -1 a) x-determinant b) y-determinant c) system determinant match the following to the pictures below.