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The function f(x) = x2 + 10x – 3 written in vertex form is f(x) = (x + 5)2 – 28. What are the coordinates of the vertex?


(–5, –28)

(–5, 28)

(5, –28)

(5, 28)

Verified Answer :

Answer:

Option A is correct

(–5, –28)

Step-by-step explanation:

For a quadratic equation:

\(y=ax^2+bx+c\)

We know that convert of quadratic into vertex form, using the method of completing the square is,

\(y = a(x-h)^2+k\)

where,

(h, k) is the vertex.

As per the statement:

The function \(f(x) = x^2 + 10x -3\)

written in vertex form is:

\(f(x) = (x+5)^2-28\)

From the above definition we have;

h = -5 and k = -28

Therefore,  the coordinates of the vertex is, (-5, -28)

The coordinates of the vertex is \(\boxed{\bf (-5,-28)}\).


Further explanation:

Given:

The function \(f(x)\) is as follows:

\(\boxed{f(x)=x^{2}+10x-3}\)

Vertex form of the function \(f(x)\) is as follows:

\(\boxed{f(x)=(x+5)^{2}-28}\)


Definition of vertex form:


The vertex form of a quadratic function is as follows:

\(\boxed{f(x)=a(x-h)^{2}+k}\)    …… (1)

Here, \((h,k)\) is the vertex of the parabola.

The standard form of the quadratic equation is as follows:

\(\boxed{f(x)=ax^{2}+bx+c}\)

If the function \(f(x)\) is written in vertex form then \((h,k)\) is the vertex of the parabola and \(x=h\) is the axis of symmetry.

Calculation:

To convert the function \(f(x)\) from standard form to vertex form first convert the function \(f(x)\) into the complete square form as shown below,

\(\begin{aligned}f(x)&=x^{2}+10x-3\\&=x^{2}+(2\cdot x\cdot 5)-3+5^{2}-5^{2}\\&=x^{2}+(2\cdot x\cdot 5)+5^{2}-3-25\\&=(x+5)^{2}-28\end{aligned}\)

Label the above equation as follows:

\(\boxed{f(x)=(x+(-5))^{2}-28}\)     ......(2)

Compare equation (1) and equation (2) to obtain the value of \(h\) and   \(k\).

The value of \(h\) and \(k\) are as follows:

\(\boxed{\begin{aligned}h&=-5\\k&=-28\end{aligned}}\)


Therefore, the vertex of the parabola is at the point \((-5,-28)\).


A direct formula to find the vertex \((h,k)\) of the parabola is,

\(\boxed{h=-\dfrac{b}{2a}\text{ and }k=f(h)}\)

The horizontal shift \(h\) is calculated as follows:

\(\begin{aligned}h&=-\dfrac{10}{2\cdot 1}\\&=\dfrac{-10}{2}\\&=-5\end{aligned}\)


The vertical shift \(k\) is calculated as follows:

\(\begin{aligned}k&=f(-5)\\&=(-5)^{2}+(10\cdot (-5)-3)\\&=25-50-3\\&=-25-3\\&=-28\end{aligned}\)


Therefore, the coordinates of the vertex is at the point \((-5,-28)\).


Thus, the coordinates of the vertex is \(\boxed{\bf (-5,-28)}\).

Learn more:

1. Learn more about vertex form https://brainly.com/question/1286775

2. Learn more about quadratic function https://brainly.com/question/1332667


Answer details:

Grade: High school

Subject: Mathematics

Chapter: Quadratic function


Keywords: Function, vertex form, quadratic function, coordinates, x2+10x-3, f(x) standard form, parabola, vertical shift, horizontal shift, degree 2, highest power is 2, quadratic equation.