Question 1010629: The following is known about three numbers: If the second number is subtracted from the sum of the first number and 3 times the third number, the result is 2. The third number plus 3 times the first number is -1. The first number plus 3 times the second number plus the third number is -16. Find the sum of the three numbers.
Found 2 solutions by josgarithmetic, MathTherapy:
Answer by josgarithmetic(39618)   (Show Source):
You can put this solution on YOUR website! The list of numbers, x, y, z.
Simplify the system.
Find the three numbers, x, y, z.
Do what method you want or need to. Elimination, substitution, matrix row reductions.
matrix?
R2=R2-3*R1, R3=R3-R1
R3=(1/2)R3
Abbreviating some steps, working just with R2 and R3 using Elimination of y,
...
and the matrix could look like
and you could use this to solve for y using R2.
and...
and...
Using R1 to find x,
 .
Answer by MathTherapy(10552)  (Show Source):
You can put this solution on YOUR website!
The following is known about three numbers: If the second number is subtracted from the sum of the first number and 3 times the third number, the result is 2. The third number plus 3 times the first number is -1. The first number plus 3 times the second number plus the third number is -16. Find the sum of the three numbers.
First number: 0
Second number: - 5
Third number: - 1
Sum of numbers: 0 - 5 - 1, or 
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