
Ayumi H. answered 04/29/18
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*1/2=0.5
1. x+y=500
2. 2x +0.5y=500-100
Here is one way to work above equations.
1A 2x + 2y=1000 (x2 both sides)
2A 2x +0.5y=400 (do 500-100 and rewrite equetion 2)
1A-2A 1.5y=600 (substract equations, and solve for y)
y= 400
(Go back to 1 and use y=400)
x+400=500
x=500-400
x=100
Or another way,
1. x+y=500
2. 2x +0.5y=500-100
2. 2x +0.5y=500-100
1. (solve for y) y=500-x
(use y=500-x in the equation 2 and rewrite it and solve for x)
2x+0.5(500-x)=400
2x+250-0.5x=400
1.5x = 400-250
1.5x =150
x=100
(use y=500-x, and x=100 to get y)
y=500-100
y=400