IDNLearn.com makes it easy to find the right answers to your questions. Our platform is designed to provide accurate and comprehensive answers to any questions you may have.

Give the properties for the equation -2x 2 - y + 10x - 7 = 0.

>Vertex

(5/2, 11/2)
(-5/2, 11/2)
(5, -7)


Sagot :

Given:

The quadratic equation is

[tex]-2x^2-y+10x-7=0[/tex]

To find:

The vertex of the given quadratic equation.

Solution:

If a quadratic function is [tex]f(x)=ax^2+bx+c[/tex], then

[tex]Vertex=\left(\dfrac{-b}{2a},f(\dfrac{-b}{2a})\right)[/tex]

We have,

[tex]-2x^2-y+10x-7=0[/tex]

It can be written as

[tex]-2x^2+10x-7=y[/tex]

[tex]y=-2x^2+10x-7[/tex]           ...(i)

Here, [tex]a=-2,b=10,c=-7[/tex].

[tex]\dfrac{-b}{2a}=\dfrac{-10}{2(-2)}[/tex]

[tex]\dfrac{-b}{2a}=\dfrac{-10}{-4}[/tex]

[tex]\dfrac{-b}{2a}=\dfrac{5}{2}[/tex]

Putting [tex]x=\dfrac{5}{2}[/tex] in (i), we get

[tex]y=-2(\dfrac{5}{2})^2+10(\dfrac{5}{2})-7[/tex]

[tex]y=-2(\dfrac{25}{4})+\dfrac{50}{2}-7[/tex]

[tex]y=\dfrac{-50}{4}+25-7[/tex]

[tex]y=\dfrac{-25}{2}+18[/tex]

On further simplification, we get

[tex]y=\dfrac{-25+36}{2}[/tex]

[tex]y=\dfrac{11}{2}[/tex]

So, the vertex of the given quadratic equation is [tex]\left(\dfrac{5}{2},\dfrac{11}{2}\right)[/tex].

Therefore, the correct option is A.