Using the denition of the derivative, find f'(x). Then nd f'(1), f'(2), and f'(3) when the derivative exists. f(x)= -x2+5x-4 f'ix)=lj (Type an expression using x as the variable.) Select the correct answer below and. if necessary, ll in the answer box to complete your choice. 0 A. f'(1)= (1. (Type an integer or a simplied fraction.) 0 B. The derivative does not exist. Select the correct answer below and. if necessary, ll in the answer box to complete your choice. 0 A. f'(2)= ' (Type an integer or a simplied fraction.) 0 B. The derivative does not exist. Select the correct answer below and, if necessary, ll in the answer box to complete your choice. O A- f'(3)= E (Type an integer or a simplied fraction.) 0 B. The derivative does not exist