SOLUTION: One number is 4 times another. Their product is 4 times their sum. Find the numbers.

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Question 263752: One number is 4 times another. Their product is 4 times their sum. Find the numbers.
Found 2 solutions by mananth, jsmallt9:
Answer by mananth(16946) About Me  (Show Source):
You can put this solution on YOUR website!
One number is 4 times another. Their product is 4 times their sum. Find the numbers.
let no be x
the other number will be 4x
4x*x= (4x+x)*4
4x^2= 20x
4x=20
x=5
& 20

Answer by jsmallt9(3758) About Me  (Show Source):
You can put this solution on YOUR website!
There is an error in a solution provided by another tutor. It is correct up to:
4x%5E2+=+20x
This is a quadratic equation. We should get one side equal to zero (by subtracting 20x from each side:
4x%5E2+-+20x+=+0
Factor:
4x%28x+-+5%29+=+0
And use the Zero Product Property which tells us that this product is zero if one of the factors is zero:
4x+=+0 or x+-+5+=+0
Solving these we get:
x+=+0 or x+=+5
For x = 0, the other number is 4x = 4(0) = 0.
For x = 5, the other number is 4x = 4(5) = 20.
So the two numbers are (0 and 0) or (5 and 20).