Question

решите систему уравнений способом сложения  

4(3x+y)-1=y-2x

2(4x-y)+19=-x

Answer 1

4(3x+y)-1=y-2x

2(4x-y)+19=-x

 

12x+4y-1=y-2x

8x-2y+19=-x

 

14x+3y=1

9x-2y=-19

 

28x+6y=2

27x-6y=-57

 

55x=-55

x=-1

 

 

4(-3+y)-1=y+2

-12+4y-1=y+2

3y=15

y=5

 

Answer 2

12X + 4Y - 1 = Y - 2X

8X - 2Y + 19 + X = 0

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 9X - 2Y + 19 = 0

12X + 2X + 4Y - Y - 1 = 0

14X + 3Y - 1 = 0

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2Y = 9X + 19

Y = 0,5*(9X + 19)

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14X + 3*0,5*(9X + 19) - 1 = 0

14X + 13.5X + 28,5 - 1 = 0

27.5X = - 27,5

X = - 1

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Y = 0.5*(- 9 +19) = 0,5*10 = 5

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ОТВЕТ: X = - 1 Y = 5