Vertex form of the quadratic equation

🏆Practice vertex representation

Vertex form of the quadratic equation

The vertex form allows us to identify, very easily, the vertex of the parabola and hence its name.

The vertex form of the quadratic function is:
Y=a(Xp)2+cY=a(X-p)^2+c

Start practice

Test yourself on vertex representation!

Find the standard representation of the following function:

\( f(x)=(x-3)^2+x \)

Practice more now

Where the values of the vertex of the parabola are (p,c)( p,c)
PP - represents the value of the XX of the vertex.
CC - represents the value of the YY of the vertex.
For example in the function:
Y=2(X3)2+5Y=2(X-3)^2+5

The vertex of the parabola is:
(3,5)(3,5)

Observe
In the formula for the vertex form there is a minus sign before PP. This is how the template is constructed, it does not mean that PP is negative.
If we obtain a negative XX vertex we will place it with a minus sign in the vertex form template and the minus will turn into plus.


Examples and exercises with solutions of the vertex form of the quadratic function

Exercise #1

Find the standard representation of the following function:

f(x)=(x3)2+x f(x)=(x-3)^2+x

Video Solution

Step-by-Step Solution

To solve this problem, we'll perform these steps:

  • Expand (x3)2(x-3)^2 using the formula for a square:
    (x3)2=x22×x×3+32=x26x+9(x-3)^2 = x^2 - 2 \times x \times 3 + 3^2 = x^2 - 6x + 9
  • Add the x x from f(x)=(x3)2+x f(x) = (x-3)^2 + x to the expanded terms:
    x26x+9+x x^2 - 6x + 9 + x
  • Combine like terms:
    x26x+x+9=x25x+9 x^2 - 6x + x + 9 = x^2 - 5x + 9

Therefore, the standard form of the function f(x) f(x) is f(x)=x25x+9 f(x) = x^2 - 5x + 9 .

Thus, the correct choice is Choice 3.

Answer

f(x)=x25x+9 f(x)=x^2-5x+9

Exercise #2

Find the vertex of the parabola

y=x26 y=x^2-6

Video Solution

Step-by-Step Solution

To solve this problem, we'll follow these steps:

  • Step 1: Identify the given information.
  • Step 2: Apply the vertex formula to find h h and k k .
  • Step 3: Determine the coordinates of the vertex.

Now, let's work through each step:
Step 1: The given quadratic equation is y=x26 y = x^2 - 6 where a=1 a = 1 , b=0 b = 0 , and c=6 c = -6 .
Step 2: We use the vertex formula:

h=b2a h = -\frac{b}{2a}
Substituting the values, h=021=0 h = -\frac{0}{2 \cdot 1} = 0 .

k=cb24a k = c - \frac{b^2}{4a}
Using the given values, k=60241=6 k = -6 - \frac{0^2}{4 \cdot 1} = -6 .

Step 3: Therefore, the vertex of the parabola is at (h,k)=(0,6) (h, k) = (0, -6) .

The solution to the problem is (0,6) (0, -6) .

Answer

(0,6) (0,-6)

Exercise #3

Find the vertex of the parabola

y=(x3)2 y=(x-3)^2

Video Solution

Step-by-Step Solution

To solve this problem, let's identify the vertex of the given parabola in the form y=(x3)2 y = (x - 3)^2 .

The parabola is already given in the vertex form of y=(xh)2+k y = (x - h)^2 + k , which is a special case of the quadratic equation where the vertex (h,kh, k) can be read directly from the equation.

  • Step 1: We compare the given equation y=(x3)2 y = (x - 3)^2 with the standard vertex form y=(xh)2+k y = (x - h)^2 + k .
  • Step 2: Notice that h=3 h = 3 and since there is no additional term added or subtracted outside the squared term, k=0 k = 0 .

Therefore, the vertex of the quadratic function y=(x3)2 y = (x - 3)^2 is (3,0) (3, 0) .

The correct choice from the multiple-choice options provided is the one that matches (3,0) (3, 0) .

The solution to the problem is the vertex (3,0) (3, 0) .

Answer

(3,0) (3,0)

Exercise #4

Find the vertex of the parabola

y=(x+1)2 y=(x+1)^2

Video Solution

Step-by-Step Solution

The equation y=(x+1)2 y = (x+1)^2 is already in the vertex form y=(xh)2+k y = (x-h)^2 + k , where (h,k)(h, k) is the vertex of the parabola.

By comparing, we have:

  • The expression inside the square is (x+1) (x+1) , which can be rewritten as (x(1)) (x - (-1)) . Thus, h=1 h = -1 .
  • The term k k is not present, which means k=0 k = 0 .

Therefore, the vertex (h,k)(h, k) of the parabola is (1,0)(-1, 0).

Thus, the correct answer is (1,0)(-1, 0).

Answer

(1,0) (-1,0)

Exercise #5

Find the vertex of the parabola

y=(x1)21 y=(x-1)^2-1

Video Solution

Step-by-Step Solution

The given equation is y=(x1)21 y = (x-1)^2 - 1 . This equation is in the vertex form, y=a(xh)2+k y = a(x-h)^2 + k , where a a , h h , and k k are constants.

In this case, the given equation can be written as y=1(x1)2+(1) y = 1 \cdot (x-1)^2 + (-1) , indicating that a=1 a = 1 , h=1 h = 1 , and k=1 k = -1 .

The vertex form of the quadratic equation allows us to directly identify the vertex of the parabola as (h,k) (h, k) .

From our identification, it is clear that the vertex (h,k) (h, k) of the parabola is (1,1) (1, -1) .

Therefore, the vertex of the given parabola is (1,1) (1, -1) .

Answer

(1,1) (1,-1)

Join Over 30,000 Students Excelling in Math!
Endless Practice, Expert Guidance - Elevate Your Math Skills Today
Test your knowledge
Start practice