SOLUTION: Find the vertex and axis of symmetry of the graph of the function. f(x) = -3x2 - 6x - 2

Algebra ->  Graphs -> SOLUTION: Find the vertex and axis of symmetry of the graph of the function. f(x) = -3x2 - 6x - 2      Log On


   

Question 1064409: Find the vertex and axis of symmetry of the graph of the function. f(x) = -3x2 - 6x - 2
Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
When the general form is:
+f%28x%29+=+a%2Ax%5E2+%2B+b%2Ax+%2B+c+
---------------------------
The formula for the vertex is:
+x%5Bv%5D+=+-b%2F%282a%29+
+a+=+-3+
+b+=+-6+
+x%5Bv%5D+=+-%28-6%29+%2F+%28+2%2A%28-3%29+%29+
+x%5Bv%5D+=+6+%2F+%28-6%29+
+x%5Bv%5D+=+-1+
------------------
Plug this result into the equation
+f%28-1%29+=+-3%2A%28-1%29%5E2+-+6%2A%28-1%29+-+2+
+f%28-1%29+=+-3+%2B+6+-+2+
+f%28-1%29+=+1+
------------------
The vertex is at ( -1, 1 )
----------------------------
The axis of symmetry is +x+=+-1+
-----------------------------------
Here's the plot:
+graph%28+400%2C+400%2C+-5%2C+5%2C+-5%2C+5%2C+-3x%5E2+-+6x+-+2+%29+