Question

What number should be added to both sides of the equation to complete the square? X^2+12x

Answer 1

The number that should be added to both sides is 16 because its half of b, which is then squared. You then get (x+4)^2=20, which you then square root both sides and get x+4=+-20 and then subtract the 4 to get x=-4+-20

Answer 2

for $ax^2+bx+c$

if a=1, and $c=(\frac{b}{2})^2$, then it comlpetes the square

$x^2+12x$

a=1, b=12

since a=1, c=$(\frac{b}{2})^2=(\frac{12}{2})^2=(6^2)=36$

add 36 to both sides of the nonexistant equation to copmlete square