SOLUTION: x^2-2x+sqrt(x^2-2x-2)=4

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Question 969578: x^2-2x+sqrt(x^2-2x-2)=4
Answer by josgarithmetic(39617) About Me  (Show Source):
You can put this solution on YOUR website!
x%5E2-2x%2Bsqrt%28x%5E2-2x-2%29=4

You need to isolate the irrational expression.
sqrt%28x%5E2-2x-2%29=-x%5E2%2B2x%2B4

Square both sides.
x%5E2-2x-2=%28-x%5E2%2B2x%2B4%29%5E2
x%5E2-2x-2=x%5E4-4x%5E3-4x%5E2%2B16x%2B16
highlight_green%28x%5E4-4x%5E3-5x%5E2%2B18x%2B18=0%29-----You could take the rest of the process. You want to try looking for Rational Roots to try to factorize the polynomial. (Rational Roots Theorem). Several possible roots to test for:
The plusses and minuses of 1,2,3,6,9; and there might be complex roots - not know until you try.

Roots Found Through Synthetic Division:
-1, 3,
Resulting coefficients after that give x%5E2-2x-6 discriminant of 28, so two more IRRATIONAL roots. General solution to quadratic equation will give -1-sqrt(7) and -1+sqrt(7).

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Solution Set:
-1, 3, -1-sqrt%287%29, and -1%2Bsqrt%287%29.
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