Answer:
k = -9
Step-by-step explanation:
You can determine the value of k in g(x)=h(x)+k by comparing the functions h and g.
Since h(x)=x^2+3 and g(x)=x^2-6 then the difference is between 3 and -6. What number when added to 3 will give -6? 3 - 9 = -6. This means k = -9.