It is known that the parabola y = x 2-1intersects the y axis at point A, and the straight line y=kxk is an arbitrary real number, so the following conclusion is not valid.
y=x？ -4x+k =x？ -4x + 4 -4 +k = (x-2)？ + k-4
Vertex A(2, k-4)
x = 2，y = -4*2 - 1 = -9
k-4 = -9，k = -5
A (2, -9)