Recall that we need to use the equation y=a(x-h)^2+k. This means that h=-2 instead of 2 otherwise it would've been (x-2)^2-6. So Renaldo made the mistake of identifying h as 2 instead of -2. The second mistake Renaldo made is that since k=-6, there should be a vertical shift of 6 units down not 2.
