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4 votes
4 votes
Hi, no steps/ explications needed. I just need a final answer

Hi, no steps/ explications needed. I just need a final answer-example-1
User Javier Eguiluz
by
2.8k points

1 Answer

9 votes
9 votes

First, let's determine the vertex of the parabola, we can do it by using the expression that gives us the coordinate x and y of the vertex, for the x-coordinate we have


x_V=-(b)/(2a)

And the y-coordinate


y_V=-(\Delta)/(4a)

And the vertex is


V=(x_V,y_V)

Applying the formula


\begin{gathered} x_V=(-12)/(2\cdot(-2))=3 \\ \\ y_V=(144-4\cdot(-2)\cdot(-19))/(4\cdot(-2))=(-8)/(8)=-1 \end{gathered}

The vertex is


V=(3,-1)

Let's plot two points to the right of the vertex, which means x > 3, I'll pick x = 4 and x = 5


\begin{gathered} f(x)=-2x^2+12x-19 \\ \\ f(4)=-2\cdot4^2+12\cdot4-19=-3 \\ \\ f(5)=-2\cdot5^2+12\cdot5-19=-9 \end{gathered}

Then two points at the right of the vertex are


\begin{gathered} (4,-3) \\ \\ (5.-9) \end{gathered}

And at the left, I'll pick 0 and 1


\begin{gathered} f(0)=-19 \\ \\ f(1)=-9 \end{gathered}

Therefore the points are


\begin{gathered} (0,-19) \\ \\ (1,-9) \end{gathered}

Final answer:


\begin{gathered} \text{ vertex:} \\ V=(3,-1) \\ \\ \text{ right points:} \\ (4,-3) \\ \\ (5,-9) \\ \\ \text{ left points:} \\ (0,-19) \\ \\ (1,-9) \end{gathered}

Hi, no steps/ explications needed. I just need a final answer-example-1
User Serge Intern
by
3.0k points