Question 876899
The sum of three numbers is 10. Two times the second number minus the first number is equal to 12. The first number minus the second number plus twice the third number equals 7. Find the numbers.
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let x=1st number
let y=2nd number
let z=3rd number
...
x+y+z=10
2y-x=12
x-y+2z=7
...
x+y+z=10
-x+2y=12
add
3y+z=22
..
-x+2y=12
x-y+2z=7
add
y+2z=19
...
3y+z=22
y+2z=19
..
3y+z=22
3y+6z=57
subtract
-5z=-35
z=7
y=-2z+19=5
x=2y-12=-2
..
1st number=-2
2nd number=5
3rd number=7