y = -(x-2)²+7
You memorize the general vertex form
y = a(x-h)²+k
You compare your equation to that:
a=-1, h=2, k=7
The vertex is the point (h,k) = (2,7)
You plot that point:
Now from that vertex, go right and left 1 unit and then "a" units.
When a is positive you go up, and when it's negative you go down.
So we go right and left 1 unit from the vertex and down 1 unit from
each because "a" is -1.
Then we sketch in the graph:
Edwin