A parabola graph has the Vertex and Y-intercept is A(0,8) and x-intercepts of B(3,0) and C(-3,0)....   Question 1) The parabola has the equation ax^2+bx+c , Use "A(0.8)" to find the value of "b"...

A parabola graph has the Vertex and Y-intercept is A(0,8) and x-intercepts of B(3,0) and C(-3,0)....
 
Question 1) The parabola has the equation ax^2+bx+c , Use "A(0.8)" to find the value of "b" and "c" from the equation ax^2+bx+c
 
Question 2) Use B(3,0) to find value of "a" which belongs to ax^2+bx+c
 
the rest of the questions are in the attachment.
 
I tried all questions but was not able to do it. 
 
Please help me :D
 
Thank you so much

Asked on by daeunkoh

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justaguide | College Teacher | (Level 2) Distinguished Educator

Posted on

The parabola passes through the points A(0, 8), B(3, 0) and C(-3,0).

The equation of the parabola is of the form y = ax^2 + bx + c.

To determine the value of c, the equation y = ax^2 + bx + c should be solved for the coordinates (0,8).

8 = a*0 + b*0 + c

c = 8

To determine a and b, y = ax^2 + bx + c should be solved for the coordinates (3,0) and (-3,0)

0 = a*(-3)^2 - 3b + c

0 = a*(3)^2 + 3b + c

As c = 8

9a - 3b + 8 = 0 and 9a + 3b + 8 = 0

Adding the two equations, 18a + 16 = 0

a = -16/18

b = 0

The graph of the parabola y = (-16/18)x^2 + 8 is:

The parabola y = (-16/18)x^2 + 8 passes through all the points A, B and C as described in the question.

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daeunkoh | eNotes Newbie

Posted on

OMG!

Thank you very much

I really appreciate your help :D I just save my life :D

Thank you sooo much

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