College

Find an equation of the form \( f(x) = ax^2 + bx + c \).

Given:
\[ f(1) = 4, \]
\[ f(2) = 13, \]
\[ f(4) = 46. \]

Solve algebraically and check using a calculator. State the steps used to perform the check.

Answer :

The equation of the form [tex]f(x)=ax^2+bx+c[/tex] that must solve algebraically and f(1)=4, f(2)=13 and, f(4)=46 is [tex]\frac{5}{2}x^2+\frac{3}{2}x+5[/tex].

Putting x = 1 in the given equation, we get

[tex]f(1)=a(1)^2+b(1)+c[/tex]

f(1) = a + b + c = 4 ...(1)

Putting x = 2 in the given equation, we get

[tex]f(2)=a(2)^2+b(2)+c[/tex]

f(2) = 4a + 2b + c = 13 ...(2)

Putting x = 4 in the given equation, we get

[tex]f(4)=a(4)^2+b(4)+c[/tex]

f(4) = 16a + 4b + c = 46 ...(3)

Using elimination method to solve the set of linear equations, we get

(2) - (1), we get

3a + b = 9 ...(4)

(3) - (2), we get

12a + 2b = 33 ...(5)

Multiplying (4) by 2, we get

6a + 2b = 18 ...(6)

(5) - (6), we get

6a = 15

a = 15/6 = 5/2

Putting a = 5/2 in (4), we get

3(5/2) + b = 9

15/2 + b = 18/2

b = 3/2

Putting the values of a and b in (1), we get

5/2 + 3/2 + c = 9

4 + c = 9

c = 9 - 4

c = 5

Hence, the equation is [tex]\frac{5}{2}x^2+\frac{3}{2}x+5[/tex].

To learn more about elimination method, here:-

https://brainly.com/question/14619835

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