Respuesta :

wegnerkolmp2741o

x+y+z=15

y =2x

z=y-20

substitute these equations into the first

x+2x+y-20 =15

now substitute 2x in for y

x + 2x +2x-20 =15

combine like terms

5x-20 =15

add 20 to each side

5x = 35

divide by 5

x=7

y =2x

y =14

z = y-20

z=14-20

z=-6

The third number is -6


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Answer:

a + b + c = 15

a + 2xb

2xb + -20c

For the first number, it is 7

For the second number, it is 14

For the third number, it is -6

MATH CHECK:

14 - 20 = (-6)

14 + (-6) = 8

8 + 7 = 15

THIRD NUMBER = (-6)