What is the least possible value of expression E = (x-1)(x-3)(x-4)(x-6)+10 for real values of x?  Select:
A) 1  B) 10  C) 9  D) 0  E) 8

Rationale: explanation : e = ( x - 1 ) ( x - 6 ) ( x - 3 ) ( x - 4 ) + 10 e = ( x 2 - 7 x + 6 ) ( x 2 - 7 x + 12 ) + 10 let x 2 - 7 x + 6 = y e = y 2 + 6 y + 10 e = ( y + 3 ) 2 + 1 minimum value = 1 , when y = - 3 answer : a
Answer: A