If f(x2 – 1) = x4 – 7x2 + k1 and f(x3 – 2) = x6 – 9x3 + k2 then the value of (k2 – k1) is _____ Choose one.
A) 6  B) 7  C) 8  D) 9  E) None of the above
Explanatory Answer   Given Data   f(x2 – 1) = x4 – 7x2 + k1   f(x3 – 2) = x6 – 9x3 + k2   Approach and Solution   When x2 = 1, f(x2 – 1) = f(1 - 1) = f(0) =(1)2 - 7(1) + k1   f(0) = - 6 + k1 ..........(1)   Essentially, we have replaced all x2 with 1.   When x3 = 2,f(x3 – 2) = f(2 - 2) = f(0) =(2)2 - 9(2) + k2   f(0) = - 14 + k2 ..........(2)   Essentially, we have replaced all x3 with 2.   Equating f(0) in equations (1) and (2)   (-6 + k1) = (-14 + k2)   or k2 - k1 = 8   The correct answer is 8hoice 8.
<result>C</result>
If f(x2 – 1) = x4 – 7x2 + k1 and f(x3 – 2) = x6 – 9x3 + k2 then the value of (k2 – k1) is _____