How do you solve using the completing the square method #x^2-12x+20=0#?

1 Answer
Jim G.
May 29, 2018

#x=2" or "x=10#

Explanation:

#"subtract 20 from both sides"#

#x^2-12x=-20#

#• " add "(1/2"coefficient of the x-term")^2" to both sides"#

#x^2+2(-6)x color(red)(+36)=-20color(red)(+36)#

#(x-6)^2=16#

#color(blue)"take the square root of both sides"#

#sqrt((x-6)^2)=+-sqrt16larrcolor(blue)"note plus or minus"#

#x-6=+-4#

#"add 6 to both sides"#

#x=6+-4#

#x=6-4=2" or "x=6+4=10#

Related questions
See all questions in Completing the Square
Impact of this question
1683 views around the world
You can reuse this answer
Creative Commons License