SOLUTION: The sum of three numbers is 20. The difference of the first two numbers is 5 and the third number is 4 times the sum of the first two

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Question 1074725: The sum of three numbers is 20. The difference of the first two numbers is 5 and the third number is 4 times the sum of the first two
Found 2 solutions by josgarithmetic, MathTherapy:
Answer by josgarithmetic(39630) About Me  (Show Source):
You can put this solution on YOUR website!
x, y, z
Assumption made here is x%3Cy.

system%28x%2By%2Bz=20%2Cy-x=5%2Cz=4%28x%2By%29%29

(corrected)---
Substituting for z,
system%28x%2By%2B4%28x%2By%29=20%2C-x%2By=5%29

system%28x%2By=4%2C-x%2By=5%29
The system here ready for use of Elimination Method.
ADD: 2y=9
highlight_green%28y=9%2F2%29
-
SUBTRACT: -2x=1
highlight_green%28x=-1%2F2%29
-
Use x and y to find z.




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(posted earlier - incorrect -
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x%2By=20-z From first equation
z=4%2820-z%29 Substituted into equation #3
z=80-4z
3z=80-----MISTAKE... All the rest below is wrong...
z=80%2F3
x%2By%2B80%2F3=20
3x%2B3y%2B80=60
3x%2B3y=-20
Simpler system in just x and y
system%283x%2B3y=-20%2C-x%2By=5%29
%283x%2B3y%29%2B%28-3x%2B3y%29=-20%2B5
6y=-15
2y=-5
y=-5%2F2
y-x=5
y-5=x
x=-5%2F2-5
x=-5%2F2-10%2F2
x=-15%2F2

Answer by MathTherapy(10557) About Me  (Show Source):
You can put this solution on YOUR website!
The sum of three numbers is 20. The difference of the first two numbers is 5 and the third number is 4 times the sum of the first two
If 1st is larger than 2nd, then 

If 1st is smaller than 2nd, then 

As usual, IGNORE all RIDICULOUS and/or NONSENSICAL answers.