## abbie1 2 years ago When solving x^2 - 4x = -7 by completing the square what value is added to both sides of the equation?

1. CalebBeavers

coefficient of x divided by 2 and then squared (-4/2)^2=?

2. abbie1

Ok so 4? I work it out and 2 and 4. So how do you know which one it is? @CalebBeavers

3. CalebBeavers

-4/2=-2 -2^2=4

4. abbie1

Ok thanks!

5. satellite73

$x^2-4x=-7$ $(x-2)^2=-7+4=-3$ $x-2=\pm\sqrt{3}i$$x=2\pm\sqrt{3}i$