Answer:
x=-11
y=-1
Step-by-step explanation:
x=4y-7
2x+9y=-31
2(4y-7)+9y=-31
8y-14+9y=-31
17=-31+14
17y=-17
x=4(-1)-7
C. x=5/2
-2x+10x=34-14
(8x=20 ) /:8
x=5/2
342
23,500