DSE 2013 qn polynomial eqn

Posted by phelps.phan on May 03, 2014; 3:01am
URL: http://discussion-forum.276.s1.nabble.com/DSE-2013-qn-polynomial-eqn-tp7588323.html

QUESTION 21. The function defined by f(x) = x^5 + 7x^3 + 13x -18
(a) may have 5 real roots.
(b) has no real root.
(c) has 3 real roots.
(d) has exactly 1 real root.

Pls help with the approach