Question 1106880
solve this by substitution: 5x+2y=9 ; y=-x-3 
5x+2(-x-3) = 9
5x-2x-6 = 9
3x = 15
x = 5
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y = -x-3 = -5-3 = -8
Ans:: (5,-8)
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and how do i solve it by graphing 
graph y = -x-3
If x = 0, y = -3
If x = -3, y = 0
Plot (0,-3) and (-3,0) and draw a line thru them.
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graph 5x+2y = 9
y = (-5x+9)/2
If x = 0, y = 9/2
If x = 1/5, y = 4
Plot (0,4.5) and (1/5,4) and draw a line thru them.
{{{graph (400,400,-10,10,-10,10,-x-3,(-5x+9)/2)}}}
The lines intersect at (5,-8)
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Cheers,
Stan H.
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