the answer
the form of function can be one of the forms given beneath:
a standard form equivalent to y = ax²+bx+c
an intercept form equivalent to y= a(x- h)(x-k)
a vertex form equivalent to y - k = (x-h)², or y = (x-h)² + k
in our case y-1=(x+5)^2, so it is written as a vertex form