# Write the vertex of the parabola y=x^2+4x.

hala718 | High School Teacher | (Level 1) Educator Emeritus

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Given the parabola y = x^2 + 4x.

Then we know that:

a = 1  b = 4   c = 0.

The vertex is given as follows.

The x-coordinate is given by:

==> Vx = -b/2a

==> vx = -4 / 2 = -2.

The y-coordinate is given by:

Vy = -(b^2 -4ac)/4a = - ( 16 - 4*1*0)/ 4 = -16/4 = -4.

==> Vy = -4.

Then the vertex of the parabola y= x^2 + 4x is V(-2, -4).

giorgiana1976 | College Teacher | (Level 3) Valedictorian

Posted on

We'll write the coordinates of the vertex of the parabola:

V(-b/2a ; -delta/4a)

a,b,c are the coefficients of the quadratic:

y = ax^2 + bx + c

Comparing, we'll identify the coefficients:

a = 1, b = 4 , c = 0

We'll calculate the x coordinate of the vertex:

xV = -b/2a

xV = -4/2

xV = -2

We'll calculate the y coordinate of the vertex:

yV = -delta/4a

delta = b^2 - 4ac

delta = 16 - 4*1*0

delta = 16

yV = -16/4

yV = -4

The coordinates of the vertex of the parabola are: V(-2 , -4).