What is the vertex for the graph of y = −3x2 + 18x − 13?

(−3, −40)

(−3, −94)

(3, 23)

(3, 14)

Question

What is the vertex for the graph of y = −3x2 + 18x − 13?

(−3, −40)

(−3, −94)

(3, 23)

(3, 14)

dumbcow · Answer

x = -b/2a

dumbcow · Answer

thats a hint, that will give you the x_coordinate of vertex

anonymous · Answer

I have gotten that far whe i did that i got -13/2(-3) = -13/-6?
is that correct?

dumbcow · Answer

no but you had the right idea.
remember its _> ax^2 +bx + c
b is always the 2nd number, a is always the 1st

dumbcow · Answer

a = -3
b = 18
c = -13

anonymous · Answer

i just need to know the vertex?

anonymous · Answer

y = −3x^2 + 18x − 13
y+13 = -3x^2+18x
(y+13)= -3( x^2-6x)
(y+13)= -3( x^2-6x+9-9)
(y+13)= -3(x^2-6x+9)+27
y+13-27=-3(x^2-6x+9)
y-14=-3(x-3)^2
or, (x-3)^2= -1(y-14)/3
it represent parabola 
with vertex(3,14)

anonymous · Answer

(3, 14)  is the answer

anonymous · Answer

ohh ok!

anonymous · Answer

:)