Question

Solve x2 + 4x = 4 for x by completing the square.

Answer 1

Answer:

D. X= ± square root of 8 - 2

Step-by-step explanation:

Given quadratic equation is \[x^{2}+4x=4\]

Rearranging the terms: \[x^{2}+4x-4=0\]

This is the standard format of quadratic equation of the form \[ax^{2}+bx+c=0\]

Here, a=1 , b=4 and c=-4.

Roots of the quadratic equation are given by \[\frac{-b \pm \sqrt{b^{2}-4ac}}{2a}\]

Substituting the values and calculating the roots:

\[\frac{-4 \pm \sqrt{(-4)^{2}-4*1*(-4))}}{2*1}\]

= \[\frac{-4 \pm \sqrt{32}}{2}\]

= \[\frac{-2*2 \pm 2*\sqrt{8}}{2}\]

= \[-2 \pm \sqrt{8}\]

Hence option D is the correct option.