+130071 x - y^2 + 8y = 13
Rearrange as
x = y^2 - 8y + 13 complete the square on y
take (1/2) of 8 =4.....square it = 16 add and subtract on the right side
x = y^2 - 8y + 16 + 13 -16 factor and simplify
x = (y - 4)^2 - 3 add 3 to both sides
(x + 3) = ( y -4)^2
We have the form ( x - h) = ( y - k)^2 where the vertex = ( h , k)
So the vertex is ( -3, 4)
See the graph here : https://www.desmos.com/calculator/6pqzy8femz
