Respuesta :
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
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