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

1 Answer
Jim G.
Mar 31, 2017

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"

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