Question

What number must you add to complete the square? x2 8x = 11

Answer 1

let the number be k
so x^2+8x+K=11+k
k=(coefficent of x/2)^2=8/2=4^2=16
so x^2+8x+16=11+16
(x+4)^2=27

x+4=+-root of 27
x=4+root of 27 or 4-root of 27

Answer 2

The answer is 16.according to apex