these are really hard for me.. Can someone help?
The vertex of y = 9 - 8x - x2 is (-4, 25)
True or False

What is the vertex for the function? y = x2 - 4x - 3
Anwsers:
(-1, 2)
(0, -3)
(1, -6)
(2, -7)

Question

these are really hard for me.. Can someone help?
The vertex of y = 9 - 8x - x2 is (-4, 25)
True or False

What is the vertex for the function? y = x2 - 4x - 3
Anwsers:
   (-1, 2) 
   (0, -3) 
   (1, -6) 
   (2, -7)

anonymous · Answer

I am assuming that when you say x2 you mean $$x^2$$

anonymous · Answer

yes

anonymous · Answer

(2,-7)

anonymous · Answer

Can you help me with the previous ones i posted?

anonymous · Answer

To do this, we find the axis of symmetry, which (in standard form of ax^2 + bx + c) is x = -b/a which in this case is -8, then we plug that into x to get the y-value of the vertex, 9, so the vertex is (-8, 9)

anonymous · Answer

so false

anonymous · Answer

can you help me with these two?
What are the values of a, b, and c in the function? List them in order with commas, such as 1,-2,3.
y = -2x2 + 5x - 4

What is the vertex for the function? (You will want to find the axis of symmetry first.) Write as an ordered pair, leaving no spaces, such as (1,-4).
y = -3x2 + 6x

anonymous · Answer

look at the standard form i posted above.

anonymous · Answer

i dnt get it

anonymous · Answer

$$y = ax^2 + bx + c$$

anonymous · Answer

??

anonymous · Answer

now you can do the first one, then look how I found the axis of symmetry above, -b/a, in this case on the second question -6/-3 = 2

anonymous · Answer

Ok, What about the first one?

anonymous · Answer

$$y = ax^2 + bx + c $$
this is the standard form of a quadratic equation, quadratic means that the highest exponent is 2 such as $$x^2$$

anonymous · Answer

OK,

anonymous · Answer

find the coefficients of x^2 and x in their respective places relative to a and b, c is the constant number on the end (-4)

anonymous · Answer

i got it :)

anonymous · Answer

One more? Thanks so much for your help! 
Which coefficient in the function tells us that the parabola for the function will point downward? y = -2x2 + 5x - 4

anonymous · Answer

Anwsers:    -2 
   5 
   -4

anonymous · Answer

the direction of the parabola depends on whether the coefficient of the x^2 term is positive or negative. If it is positive such as 5x^2 it will point up, but -3x^2 would point down. In this case -2 is the coefficient which means it points downward

anonymous · Answer

ohhh kk!!

anonymous · Answer

HOW DO I FIGURE THIS OUT $$6\sqrt{2} - 3\sqrt{2}$$