Duplicate Question
The question on this page has been marked as a duplicate question.
Original Question
What is the equation in standard form, of a parabola that models the values in the table? x f(x) -2 4 0 -6 4 70Asked by Link
                what is the equation in standard form of a parabola that models the value in the table? x -2,0,4 fx 1,5,-59 
            
            
        Answers
                    Answered by
            Reiny
            
    so you have the points:
(-2,1), (0,5), and (4,-59)
let the function be
y = ax^2 + bx + c
for (0,5)
5 = 0 + 0 + c -----> c = 5
so we could reduce our equation to
y = ax^2 + bx + 5
for (-2,1)
1 = 4a - 2b + 5
4a - 2b = -4
2a - b = -2 ***
for (4, -59)
-59 = 16a + 4b + 5
16a + 4b = -64
4a + b = -16 ****
add *** and ****
6a = -18
a = -3
into ****
-12 + b = -16
b = -4
y = -3x^2 - 4x + 5
change to whatever version of the parabola you need
A quick mental check shows that all 3 points lie on the curve
    
(-2,1), (0,5), and (4,-59)
let the function be
y = ax^2 + bx + c
for (0,5)
5 = 0 + 0 + c -----> c = 5
so we could reduce our equation to
y = ax^2 + bx + 5
for (-2,1)
1 = 4a - 2b + 5
4a - 2b = -4
2a - b = -2 ***
for (4, -59)
-59 = 16a + 4b + 5
16a + 4b = -64
4a + b = -16 ****
add *** and ****
6a = -18
a = -3
into ****
-12 + b = -16
b = -4
y = -3x^2 - 4x + 5
change to whatever version of the parabola you need
A quick mental check shows that all 3 points lie on the curve
                                                    There are no AI answers yet. The ability to request AI answers is coming soon!
                                            
                Submit Your Answer
We prioritize human answers over AI answers.
If you are human, and you can answer this question, please submit your answer.