SOLUTION: The sum of three numbers is -48. The first number is twelve more than the second number,and the third number is 20 less than twice the second number. Find the three numbers

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Question 126563: The sum of three numbers is -48. The first number is twelve more than the second number,and the third number is 20 less than twice the second number. Find the three numbers
Found 2 solutions by marcsam823, checkley71:
Answer by marcsam823(57) About Me  (Show Source):
You can put this solution on YOUR website!
Let x = second number
Let x + 12 = first number
Let 2x - 20 = third number (twenty less than two times the second
Set up the equation - the sum of the numbers is:
1st number + 2nd number + 3rd number = -48
%28x+%2B+12%29+%2B+%28x%29+%2B+%282x+-+20%29+=+-48
Combine like terms and solve:
4x+-+8+=+-48
4x+=+-40
x+=+-10
-10 is the SECOND number
Substite:
x+%2B+12+=+-10+%2B+12+=+2First number
2x+-+20+=+2%28-10%29+-20+=+-40 Third number
Check:
%28x+%2B+12%29+%2B+%28x%29+%2B+%282x+-+20%29=+-48
%28-10%29+%2B+%282%29+%2B+%28-40%29+=+-48%29
-48+=+-48
This checks out. The three numbers are -10, 2 and -40

Answer by checkley71(8403) About Me  (Show Source):
You can put this solution on YOUR website!
x+y+z=-48
x=y+12
z=2y-20
Replacing x & z with (y+12) & (2y-20)
(y+12)+y+(2y-20)=-48
y+12+y+2y-20=-48
4y=-48-12+20
4y=-40
y=-40/4
y=-10 answer.
x=-10+12=2 answer.
z=2*-10-20=-20-20=-40 answer.
PROOF.
-10+2-40=-48
-48=-48