If f(x)is a quadratic polynomial such that f(2)= -3 and f(-2)= 21 then the coefficient of x in f(x)is ?

Let f(x) = ax² + bx + c

Given, f(2) = -3

This gives 4a + 2b + c = -3        ... (1)

 

Given, f(-2) = 21

This gives 4a - 2b + c = 21        ... (2)

 

Subtracting (2) from (1), we get,

4b = -24

b = -6

 

Thus, the coefficient of x in f(x) is b = -6.