Find the maximum value of the function f(x)=x−5 if x is a number between -5 and 13.
Choose one.
A) 6 B) 7 C) 8 D) 9 E) none

Rationale: solution : since f ( x ) is a linear function whose slope is 1 , a positive number , it is strictly increasing for all x . therefore its maximal value is reached for the largest value of x , x = 13 and f ( x ) = 13 - 5 = 8 . answer c
Answer: C