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Write a quadratic function to represent the data in the table.

x y
1 55
2 65
3 71
4 73
5 71

User Stef Hej
by
7.9k points

1 Answer

6 votes

Answer:

Explanation:

x y

1 55

2 65

3 71

4 73

5 71

f(x) = -x^2 + 16x + 55

Steps:

Steps:

1. Calculate the average rate of change (slope) for each pair of points:

(65-55)/(2-1) = 10

(71-65)/(3-2) = 6

(73-71)/(4-3) = 2

(71-73)/(5-4) = -2

2. Use the average rate of change to calculate the y-intercept:

y-intercept = y - (slope x x)

y-intercept = 73 - (2 x 5) = 63

3. Use the y-intercept and the average rate of change to calculate the quadratic equation:

f(x) = ax2 + bx + c

f(x) = (slope x x) + bx + y-intercept

f(x) = (-2 x x) + bx + 63

4. Use the first point to calculate the value of b and c:

f(1) = (-2 x 1) + b(1) + 63

f(1) = -2 + b + 63

f(1) = 55

55 = -2 + b + 63

b = 16

5. Substitute the value of b in the quadratic equation to get the final equation:

f(x) = -x^2 + 16x + 63

User ArtemKh
by
8.4k points

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