How do you solve x22x+2 by completing the square?

1 Answer
Jun 12, 2015

x=1+i

x=1i

Explanation:

Make a perfect square trinomial by completing the square. A perfect square trinomial has the form of a2+2ab+b2=(a+b)2 or a22ab+b2=(ab)2.

x22x+2=0

Subtract 2 from both sides of the equation.

x22x=2

Divide the coefficient of the x term by 2 and square the result. Add it to both sides of the equation.

22=1; 12=1

x22x+1=2+1 =

x22x+1=1

There is now a perfect square trinomial on the left side of the equation.

Factor the trinomial.

(x1)2=1

Take the square root of both sides and solve for x.

x1=±1

x1=±i

x=1±i