Question 280334
solve by determinants 6x-21=3y, y=-2x+13
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2x-y = 7
2x+y = 13
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|2 -1 -7|
|2 1 -13|
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Det = 2+2 = 4
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Det*x = 13+7 = 20
x = 5
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Det*y = 26-14 = 12
y = 3