Question

1.Which equation represents the axis of symmetry of the function y = –2x² + 4x –6?
y = 1
x = 1
x = 3
x = –3
2.What are the coordinates of the vertex of the graph of the function y = –x² + 6x –11?
(3, –2)
(3, 16)
(–3, –29)
(–3, –20)
3.What are the coordinates of the vertex of the graph of the function y = –3x² –12x + 3?
(–2, 29)
(2, –15)
(2, –9)
(–2, 15)

Answer 1

x= -b/2a formula for axis of symmetry

Answer 2

General form of equation: y=ax^2+bx+c
To find axis of symmetry use discriminant x=(-b/2a)
To find the coordinates of the vertex use the x from the discriminate and plug it into the function to find y

Answer 3

thx guys but that really didnt help me any.. :/

Answer 4

ax^2 + bx + c
for 1)
b=4, a= -2
axis of symmetry = -(4)/2(-2)

Answer 5

1)Axis of symmetry: x=-(4)/2(2)=-4/4=-1; axis of symmetry is -1

2)Vertex: use the same equation to find x, x=-(6)/2(-1)=-6/-2=3
Then use that x in the original equation: y=-(3)^2+6(3)-11=-2
Vertex is at (3,-2)

Answer 6

for 1) the a is -2 not 2, which changes the sign of your answer

Answer 7

x=3?

Answer 8

no 2 is ok
no 3 is b

Answer 9

you did it right differentiate set x to zero , get x and plug it back in to get y