SOLUTION: write the equation of the axis of symetry and find the coodinates. identify the vetext as a maximum or miumum y=3x^2-6x-4

Algebra ->  Quadratic-relations-and-conic-sections -> SOLUTION: write the equation of the axis of symetry and find the coodinates. identify the vetext as a maximum or miumum y=3x^2-6x-4      Log On


   



Question 47865: write the equation of the axis of symetry and find the coodinates. identify the vetext as a maximum or miumum

y=3x^2-6x-4

Found 2 solutions by Nate, stanbon:
Answer by Nate(3500) About Me  (Show Source):
You can put this solution on YOUR website!
y = 3x^2 - 6x - 4
v(-b/2a,f(x))
Since the parabola is vertical, the Axis of Symmetry is: x+=+-b%2F2a
x+=+1
Since the value of a is positive, the parabola opens upwards. The vertex is a minimum.
graph%28600%2C600%2C-10%2C10%2C-10%2C10%2C3x%5E2-6x-4%29

Answer by stanbon(75887) About Me  (Show Source):
You can put this solution on YOUR website!
write the equation of the axis of symetry and find the coodinates. identify the vetext as a maximum or miumum

y=3x^2-6x-4
Put this in the form (x-h)^2 = 4p(y-k) by completing the square, as follows:
y+4+3=3(x^2-2x+1)
y+7=3(x-1)^2
(x-1)^2=(1/3)(y+7)
Axis of symmetry: x=1
Vertex (1,-7) is a minimum
Solved by pluggable solver: SOLVE quadratic equation with variable
Quadratic equation ax%5E2%2Bbx%2Bc=0 (in our case 3x%5E2%2B-6x%2B-4+=+0) has the following solutons:

x%5B12%5D+=+%28b%2B-sqrt%28+b%5E2-4ac+%29%29%2F2%5Ca

For these solutions to exist, the discriminant b%5E2-4ac should not be a negative number.

First, we need to compute the discriminant b%5E2-4ac: b%5E2-4ac=%28-6%29%5E2-4%2A3%2A-4=84.

Discriminant d=84 is greater than zero. That means that there are two solutions: +x%5B12%5D+=+%28--6%2B-sqrt%28+84+%29%29%2F2%5Ca.

x%5B1%5D+=+%28-%28-6%29%2Bsqrt%28+84+%29%29%2F2%5C3+=+2.52752523165195
x%5B2%5D+=+%28-%28-6%29-sqrt%28+84+%29%29%2F2%5C3+=+-0.527525231651947

Quadratic expression 3x%5E2%2B-6x%2B-4 can be factored:
3x%5E2%2B-6x%2B-4+=+3%28x-2.52752523165195%29%2A%28x--0.527525231651947%29
Again, the answer is: 2.52752523165195, -0.527525231651947. Here's your graph:
graph%28+500%2C+500%2C+-10%2C+10%2C+-20%2C+20%2C+3%2Ax%5E2%2B-6%2Ax%2B-4+%29

Cheers,
Stan H.