Question

ll

Answer 1

There are two ways: convert to y= a(x-h)^2+k and the vertex is at (h,k)
or use the x-value of the vertex is at x = -b/(2a)
then use that x value to find the y value

the b and a in -b/(2a) are the coefficients:
y= a x^2 + b x + c

Answer 2

thanks so i got (2, -2)

Answer 3

@phi

Answer 4

That's good.

Answer 5

yup