Question

47. in the parabola, = 3^2 + 12 + 11, the vertex isA.(2,1) b(-2,-1) c (2,-1) d (-2,1)e (3,11)

Answer 1

The Solution.

The given parabola is

`y=3x^2+12x+11`

Let the vertex of the given parabola be (h,k).

So,

`\begin{gathered} h=-(b)/(2a) \\ \text{Where a=3,b=12,c=11} \end{gathered}`

Substituting these values, we get

`h=-(12)/(2*3)=-(12)/(6)=-2`

Now, substituting -2 for x in the given parabola, we get

`\begin{gathered} k=3(-2)^2+12(-2)+11 \\ k=3(4)-24+11 \\ k=12-24+11 \\ k=-12+11=-1 \end{gathered}`

So, the vertex of the given parabola is (-2,-1)

Thus, the correct answer is option B.