Which system of equations is represented by the graph?


A. y = x2 − 5x − 3
6x − y = −27

B.y = x2 − 5x + 3
6x − y = 27

C. y = x2 + 5x + 3
6x + y = −27

D. y = x2 + 5x − 3
6x + y = 27

Which system of equations is represented by the graph A y x2 5x 3 6x y 27 By x2 5x 3 6x y 27 C y x2 5x 3 6x y 27 D y x2 5x 3 6x y 27 class=

Respuesta :

C. y = x2 + 5x + 3
6x + y = −27

Answer:

The correct option is C.

Step-by-step explanation:

The vertex form of a parabola is

[tex]y=a(x-h)^2+k[/tex]              .... (1)

Where, (h,k) is vertex.

From the given figure it is clear that the vertex of the parabola is at (-2.5, -3.25) and the y-intercept is (0,3).

Substitute h=-2.5, k=-3.25, x=0 and y=3 in equation (1) to find the value of a.

[tex]3=a(0+2.5)^2-3.25[/tex]

[tex]3+3.25=6.25a[/tex]

[tex]6.25=6.25a[/tex]

Divide both sides by 6.25.

[tex]1=a[/tex]

Substitute h=-2.5, k=-3.25 and a=1 in equation (1), to find the equation of parabola.

[tex]y=1(x+2.5)^2-3.25[/tex]

[tex]y=x^2+5x+6.25-3.25[/tex]

[tex]y=x^2+5x+3[/tex]

The equation of parabola is [tex]y=x^2+5x+3[/tex].

If a line passes through two points then the equation of line is

[tex]y-y_1=\frac{y_2-y_1}{x_2-x_1}(x-x_1)[/tex]

The line passes through two points (-6,9) and (-5,3).

[tex]y-9=\frac{3-9}{-5+6}(x+6)[/tex]

[tex]y-9=\frac{-6}{1}(x+6)[/tex]

[tex]y-9=-6(x+6)[/tex]

[tex]y-9=-6x-36[/tex]

Add 9 on both the sides.

[tex]y=-6x-36+9[/tex]

[tex]y=-6x-27[/tex]

The equation of line is y=-6x-27.

Therefore the correct option is C.