SOLUTION: 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

Algebra ->  Coordinate Systems and Linear Equations -> SOLUTION: 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       Log On


   

Question 180757: The (x,y) is the solution set to the system 2x-y=-4
5x+9y=13, then
a. -3 b. 0 c. -3 d. 0
Answer by Mathtut(3670) About Me  (Show Source):
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The (x,y) is the solution set to the system 2x-y=-4
5x+9y=13, then
a. -3 b. 0 c. -3 d. 0 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%28x=-1%29
:
plug x's found value into eq 1 or 2 . I choose eq 1
:
2(-1)-y=-4
:
highlight%28y=2%29
:
so we have x=-1 and y=2
:
therefore c is the answer