Answer:
There is only one zero for this function, and it takes place at x = 3
Which seems to agree with answer "c" in your list of options
Explanation:
This is the equation of a line with a slope different from zero, therefore, there is only one zero (crossing of the x-axis) for it. We can find it by solving for x when y = 0:
y = - 3 x + 9
0 = - 3 x +9
3 x = 9
x = 9/3
x = 3