SOLUTION: what is the vertex and axis of symetry of parabola with equation y=2x^2 +8x+3. I tried to complete the square and i got the vertex to be (-2,-1) but the answer sheet the teacher g

Question 37841: what is the vertex and axis of symetry of parabola with equation y=2x^2 +8x+3.
I tried to complete the square and i got the vertex to be (-2,-1) but the answer sheet the teacher gave says the vertex is (-2,-5)? What did I do wrong?
Answer by stanbon(75887) (Show Source): You can put this solution on YOUR website!
what is the vertex and axis of symetry of parabola with equation y=2x^2 +8x+3.
y-3=2(x^2+4x
Complete the square on the right side and maintain the equality
by adding the same term to he left side, as follows:
y-3+2(4)=2(x^2+4x+4)
y+5=2(x+2)^2
Axis of symmetry is x=-2
Vertex is (-2,-5)
Cheers,
Stan H.
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