For each quadratic function, find the axis of symmetry of its graph.
y = 3x^2 - 2x - 6

Question

For each quadratic function, find the axis of symmetry of its graph.
y = 3x^2 - 2x - 6

unklerhaukus · Answer

what is the graph doing at x=0

anonymous · Answer

thats the only question srry so idk

unklerhaukus · Answer

try and see
$$y = 3x^2 - 2x - 6 $$
when x=0
$$y=3\times 0^2-2\times0-6$$

anonymous · Answer

so then would it be -18. y=-18

unklerhaukus · Answer

0^2=0

unklerhaukus · Answer

so when x=0, y=-6

anonymous · Answer

so can i write it like this (0,-6)

unklerhaukus · Answer

yeh but that only a point in the parabola,

unklerhaukus · Answer

what is y when x>0,   x<0

anonymous · Answer

for some reason i put (0,-6) and I got it wrong

unklerhaukus · Answer

well the axis of symmetry is a line and (0,-6) is just a point

anonymous · Answer

so then thats not the answer

unklerhaukus · Answer

If you look at the equation
$$y = 3x^2 - 2x - 6 $$

and then take the derivative with respect to x$$\frac{\text dy}{\text d  x}= 36x - 2 $$

you will get dy/dx=0 when x=1/18,
dy/dx =0 mean you at at a turning point on the line,
since a parabola only has one turning point this is your x value of the axis of symetry