Answer:
$36
Explanation:
we need to find the cost of 12 items, and the function of determining the cost is C(x)=2x+12, where x is the number of items (the input value of the function)
we know that there are 12 items, so in this function, x=12
substitute x as 12 in the function; the x in C(x) also gets substituted as 12, as 12 is the input value and the value of C(x) is the output
C(12)=2(12)+12
multiply
C(12)=24+12
add
C(12)=36
that means, for 12 items, the cost will be $36