Solve the equation x^2+4x-7=0 by completing the square. What are the solutions?

A. (2 + sqrt. of 11, 2 - sqrt. of 11)

B. (-2 sqrt of 11, - 2 - sqrt of 11)

C. (2+sqrt of 7, 2 + sqrt of 7)

X^2+4x-7=0

with form

ax^2+bx+c=0

move c to the other side

x^2+4x=7

complete square:

divide b=4 by 2

4*1/2=2

square it

2^2=4

add 4 to both sides

x^2+4x=7

x^2+4x+4=7+4

x^2+4x+4=11

transform to polynom

(x+2) ^2=11

calculate root

x+2=+/-sqrt (11)

x=-2+/-sqrt (11)

so option B.