in the example how did you get ( -2.3) as an answer
It's how you read the vertex form to derive the max/min point. If the vertex form is say "m(x-p)^2 +q" then the vertex is (p, q). In other words the vertex's x-coordinate is found by changing the sign of the number after the x in the brackets, and the y-coordinate is equal to the constant term being added/subtracted outside the brackets. So the answer here is (-2, -3)
thanks sir , still confused though :/
Thanks for letting me know. Will go through it in class again tomorrow.