Respuesta :

Using Substitution method:

2 x - y = 23 --------------- equation 1

x- 9 = -1 ----- equ 2

x = -1 + 9

x = 8 .......(1)

put x = 8 in equ 1

2 (8) - y = 23

16 - y = 23

16 - 23 = y

y = -7.....(11)

Conclusion : x = 8, y = -7