Question 180757
The (x,y) is the solution set to the system 2x-y=-4
                                            5x+9y=13, then
a. -3 <x<0 and -5 <y<0
b. 0<x<4 and -5 <y<0
c. -3 <x<0 and 0<y<5
d. 0<x<4 and 0<y<5

2x-y=-4.....eq 1
5x+9y=13....eq 2
:
rewrite eq 1 to y=2x+4 and plug that value into eq 2
:
5x+9(2x+4)=13
:
5x+18x+36=13
:
23x=-23
:
{{{highlight(x=-1)}}}
:
plug x's found value into eq 1 or 2 . I choose eq 1
:
2(-1)-y=-4
:
{{{highlight(y=2)}}}
:
so we have x=-1 and y=2
:
therefore c is the answer