How do you solve using the completing the square method x2−4x+2=0?

1 Answer
Lucky13
Apr 11, 2017

y=(x−2)2−2

Explanation:

The completing the square form is:
y=(x+a)2+b

The "a" term will be equal to the middle term divided by two. I.e. −42=−2.

This means that you now have the following:

y=(x−2)2+b

Because the completing the square form is equivalent to your original equation you have:

x2−4x+2=(x−2)2+b
x2−4x+2=x2−4x+4+b <-- I expanded the right-hand side
b=−2 <--After simplifying you can find the "b"-term

Related questions
See all questions in Completing the Square
Impact of this question
1732 views around the world
You can reuse this answer
Creative Commons License