How do you solve using the completing the square method #x^2+ 8x + 2 = 0#?

1 Answer
Apr 27, 2017

Answer:

#x=-4+-sqrt14#

Explanation:

#"to use the method of "color(blue)"completing the square"#

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

#"that is add " (8/2)^2=16" to both sides"#

#rArr(x^2+8xcolor(red)(+16))+2=0color(red)(+16)#

#rArr(x+4)^2+2=16#

#"subtract 2 from both sides"#

#(x+4)^2cancel(+2)cancel(-2)=16-2#

#rArr(x+4)^2=14#

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

#sqrt((x+4)^2)=+-sqrt14#

#rArrx+4=+-sqrt14#

#rArrx=-4+-sqrt14#