HELP WILL MARK BRAINLIEST!!!
A quadratic function for a parabola has axis of symmetry x = -2, points (-3, 2) and (0,11) and opens upward. What is the value of a? What is the vertex?​

Respuesta :

Answer:

Let's see what to do buddy..

Step-by-step explanation:

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STEP (1)

We know that the quadratic functions form are like this :

[tex]y = a \: {x}^{2} + b \: x + c [/tex]

The quadratic function opens upward so ;

[tex]a > 0[/tex]

The axis of parabolic symmetry passes through the vertex of the parabolic.

So we know that x vertex is equal to -2.

The vertex's x is finding from this equation:

[tex]x = - \frac{b}{2a} \\ [/tex]

So we have :

[tex] - 2 = - \frac{b}{2a} \\ [/tex]

Multiply the sides of the equation by 2a :

[tex]b = 4a[/tex]

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STEP (2)

A quota passes through points (-3,2) and (0,11) , so points (-3,2) and (0,11) must be true in the quota equation.

[tex]y = f(x) = a{x}^{2} + bx + c \\ \\b = 4a \\ \\ y = f(x) = a {x}^{2} + 4ax + c [/tex]

[tex]f( - 3) = 2 \\ \\ a ({ - 3})^{2} + 4a( - 3) + c = 2 \\ \\ 9a - 12a + c = 2 \\ \\ - 3a + c = 2 \\ \\ \\ \\ f(0) = 11 \\ \\ a ({0})^{2} + 4a(0) + c = 11 \\ \\ c = 11 [/tex]

[tex] - 3a + c = 2 \\ \\ c = 11 \\ \\ - 3a + 11 = 2 \\ 11 \: goes \: to \: the \: other \: side \: \\ \\ - 3a = 2 - 11 \\ - 3a = - 9 \\ divided \: the \: sides \: of \: the \: equation \: by \: - 3 \\ a = 3[/tex]

And we're done.

Thanks for watching buddy good luck.

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