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x^2+x+√(x^2 +x)-2=0
I have no clue any help please

2007-10-21 04:12:01 · 1 answers · asked by mormar 1 in Science & Mathematics Mathematics

1 answers

Hint: Try the substitution u = √x²+x
as this equation is quadratic in x²+x.
Then u²+u-2 = 0.
and u must be positive.
So (u+2)(u-1) = 0.
and u = 1.
So √x²+x = 1
x²+x-1 = 0
x = ½(-1 + √5)
and x = ½(-1-√5)
If x = ½(-1 + √5)
x² = ½(3- √5)
and x²+x = 1
so ½(-1 + √5) is a solution.
Similarly, if
x = ½(-1 - √5)
x² = ½(3 + √5)
and x²+x = 1.
So all real solutions are given by
x = ½(-1 + √5)
and
x = ½(-1 - √5).

2007-10-21 04:31:07 · answer #1 · answered by steiner1745 7 · 0 0

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