Solve by substitution
3x y=-9
x-2y=-10

:  3x + y = 9 
y = 9 - 3x 

x - 2y = 10 
y = (x - 10)/2 

2(9 - 3x) = x - 10 
18 - 6x = x - 10 
7x = 28 
x = 4 

y = 9 - 3(4) 
y = 9 - 12 
y = - 3 

x = 4, y = - 3 

Proof—2nd equation: 
4 - 2(- 3) = 10 
4 + 6 = 10

Hope this helps :)

I'm just guessing, but my answer would c. 0 to 300.

Ibelieve the answer is c