Answer:
k=7
Other root=3
Explanation:
If x=4 is a root of the given equation, then it satisfies the given equation.
4^2-k(4)+12=0
We can solve this equation for k.
16-4k+12=0
28-4k=0
28=4k
28/4=k
7=k
So the equation is x^2-7x+12=0
Factor form is (x-3)(x-4)=0 since-3(-4)=12 and -3+-4=-7.
This implies x=3 and x=4 are roots.