Question

Rewrite f(x) into vertex form by completing the square f(x)=−x2+8x+9​

Answer 1

vertex = ( 4 , 25 )

Explanation:

given a parabola in standard form y = a x 2 + b x + c x ; a ≠ 0

then the x-coordinate of the vertex is

X vertex=-b/2a

y=-x2+8x+9 with a=-1 b=8 c=9

X vertex= -8/-2=4

substitute the value on the equation

Y vertex = -(4)squared+8(4)+9=25