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The sum of three numbers is 19. Two times the first number increased by six times the second number plus the third number is 12. The sum of three
times the first number and eight times the second number, increased by the third number is -14. If the first number is represented by x, the second
number is represented by y, and the third number is repre d by z, which of the systems of equations below can be used to determine the three
numbers?
Please help due tonight!!

Respuesta :

Answer:

Step-by-step explanation:

 x+    y+z=19   ...(1)

2x+6y+z=12   ...(2)

3x+8y+z=-14    ...(3)

(2)-(1) gives

x+5y =-7   ...(4)

(3)-(1)  gives

2x+7y= -33   ...(5)

multiply (4) by 2

2x+10y=-14   ...(6)

(6)-(5) gives

3y=19

y=19/3

x+95/3=-7

x=7+95/3=(21+95)/3=116/3

from (1)

116/3+19/3+z=19

(116+19)/3+z=19

135/3+z=19

45+z=19

z=19-45=-26