m is the smallest positive integer such that for any integer n < m, the quantity n3−7n2+11n−5 is positive. What is the value of m?
Option (d)
n=1 is a root of the equation
(n−1)(n2−6n+5)=(n−1)2(n−5)
Now, n−12 is always positive.
Now, for n < 5, the expression gives a negative quantity.
Therefore, the least value of n will be 6. Hence m = 7 .