Question

Evaluate f(x) when x = 9

Answer 1

Answer :  C

i.e. f(x) =12 when x = 9

Explanation :

Since we have given that

$f(x) =6x^2+2\text{ if} -6$

x=9 lies in the interval [9,13]

so f(x) will be 12 for  x=9

in another interval i.e (-6,9)

x can't be 9 as it is an open interval which does not include 9 .

so we'll go for f(x)=12 when x=9.

Answer 2

when x = 9, use the bottom equation   because 9 ≤ 9 < 13

f(x) = 12

f(9) = 12   there is no "x" to replace with 9 so the value doen't change.

Answer: C