The vertex of this parabola is at (2,-1). When the y value is 0, the value is 5.
What is the coefficient of the squared term in the parabola's equation?
(2.-1)
A.-3
B. -4
c. 4
D. 3

Respuesta :

Answer:

Option D.

Step-by-step explanation:

The vertex form of a parabola along y-axis is

[tex]y=a(x-h)^2+k[/tex]

where, (h,k) is vertex and, a is constant and it is equal to coefficient of the squared term in the parabola's equation.

The vertex of the parabola is (2,-1). So, h=2 and k=-1.

[tex]y=a(x-2)^2-1[/tex]

The graph passes through (5,0). So,

[tex]0=a(5-2)^2-1[/tex]

[tex]1=9a[/tex]

[tex]\dfrac{1}{9}=a[/tex]

It means coefficient of the squared term is 1/9, which is not the option. So, parabola must be along the x-axis.

The vertex form of a parabola along x-axis is

[tex]x=a(y-k)^2+h[/tex]

where, (h,k) is vertex and, a is constant and it is equal to coefficient of the squared term in the parabola's equation.

The vertex of the parabola is (2,-1). So, h=2 and k=-1.

[tex]x=a(y+1)^2+2[/tex]

The graph passes through (5,0). So,

[tex]5=a(0+1)^2+2[/tex]

[tex]5-2=a[/tex]

[tex]3=a[/tex]

It means coefficient of the squared term is 3.

Therefore, the correct option is D.