How do you solve using the completing the square method #x^2 + 6x + 7 = 0#?

1 Answer
Mar 31, 2017

Answer:

#x_1~~-1.6,x_2~~-4.4" to 1 dec. place"#

Explanation:

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

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

#rArrx^2+6xcolor(red)(+3)^2+7=0color(red)(+3)^2#

#rArrx^2+6x+9=9-7#

#rArr(x+3)^2=2#

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

#sqrt((x+3)^2)=+-sqrt2#

#rArrx+3=+-sqrt2#

#rArrx_1=sqrt2-3~~-1.6" to 1 dec. place"#

#rArrx_2=-sqrt2-3~~-4.4" to 1 dec. place"#