n1java n1java 25-11-2020 Mathematics contestada 12. If 3x + 4y = -1 and x - 2y = 3, then y= a) 1 b) 2 c)-1 d) 3 e) 4 13. If 2x - 4y = 8 and y=2x + 1, then x a) 2 b) 4 c) -3 d) 3 e) -2