m

Question

m

anonymous · Answer

I know it will be a max value since it's a negative parabola..

campbell_st · Answer

can you differentiate?

cwrw238 · Answer

yes a maxim

anonymous · Answer

I also think it is either max of 9 or -9

anonymous · Answer

but not confident in my arithmetic here

campbell_st · Answer

ok... do you know how to differentiate..?

or find the line of symmetry of a parabola..?

anonymous · Answer

i do not  :(

campbell_st · Answer

ok... here is the easy way....

every parabola has a line of Symmetry. The max or min value is on the line of symmetry. 

to find the line of symmetry for a parabola

$$y = ax^2 + bx + c$$

use 

$$x = \frac{-b}{2a}$$

using your question 

a = -1 and b = 2

the line of symmetry is

$$x = \frac{-2}{2 \times -1}$$

so the line of symmetry is

x = 1

does this make sense|dw:1350766627362:dw|