In order to find the zeros in a quadratic in vertex form, you need to follow a number of steps. They have been outlined for you along with a sample problem.
y = (x - 2)^2 - 16
After getting the original form, you can place a 0 in for y. In is where the graph will cross the x-axis, so it is where you will find both of your zeros.
0 = (x - 2)^2 - 16
Now take the constant and add it to both sides. In this equation, -16 is your constant. So, we'll add 16 to both sides to begin to solve.
16= (x - 2)^2
Now we can take the square root of both sides. After we do so, we take both the positive and negative version of what we get. This is because both 4 and -4 squared is equal to 16.
+/-4 = x - 2
Now we add 2 to both sides to get us what is left of x.
2 +/- 4 = x
Now that we have a final form such as this, we can separate and get two answers for our two zeros.
2 + 4 = 6
2 - 4 = -2