Solve the polynomial inequality
posted by Jill on .
Solve the polynomial inequality and graph the solution set on a real number line. Express the solution set in interval notation.
x^3+x^2+4x+4<0
The solution set is=

x^3+x^2+4x+4<0
(x^2(x+1) + 4(x+1) < 0
(x+1)(x^2+4) < 0
well, x^2 + 4 is always positive, so the only way the whole thing < 0 if
x+1 < 0
x < 1
check:
good ol' Wolfram webpage
http://www.wolframalpha.com/input/?i=plot+y+%3D+x%5E3%2Bx%5E2%2B4x%2B4
notice where the curve is below the xaxis ? 
Thank you!!!