Question

find the value of k such that the equation has one real root
x^2+12+k=0

Answer 1

to have 1 root it needs to in the form (x-r)^2 = 0
(x-r)^2 = x^2 -2xr +r^2

-2r = 12 --> r = -6
r^2 = k
--> k = 36

Answer 2

you could also think of completing the square:
take half of 12 and square it

Answer 3

I did not think of doing that thanks