SOLUTION: The sum of a number and its square is 4 more than twice the number. Find the number.

Question 1085210: The sum of a number and its square is 4 more than twice the number. Find the number.
Found 3 solutions by stanbon, addingup, math_helper:
Answer by stanbon(75887)   (Show Source): You can put this solution on YOUR website!
The sum of a number and its square is 4 more than twice the number. Find the number.
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Equation:
x + x^2 = 2x+4
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x^2 -x - 4 = 0
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Quadratic formula::
x = [1 +-sqrt(1-4*-4)]/2
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x = [1 +- sqrt(17)]/2
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x = (1/2)+(1/2)sqrt(17) or x = (1/2)-(1/2)sqrt(17)
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Cheers,
Stan H.
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Answer by addingup(3677)   (Show Source): You can put this solution on YOUR website!
x+x^2 = 2x+4
Subtract 2x+4 from both sides:
x^2-x-4 = 0
x^2-x = 4
x^2-x+1/4 = 17/4
(x-1/2)^2 = 17/4
x-1/2 = sqrt(17)/2 or x-1/2 = -sqrt(17)/2
x = 1/2+sqrt(17)/2 or x = 1/2-sqrt(17)/2
Answer by math_helper(2461)   (Show Source): You can put this solution on YOUR website!

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