Solve the inequality. x^3+9x^2-108 less than or equal to 0.

Then write in interval noation.

Please can you show me step by step on how you got the answer. I have tries and I am very confused.

2 answers

first this software is very handy for polynomials and seeing their graphs:
http://mathportal.org/calculators/polynomials-solvers/polynomial-graphing-calculator.php
(x+6)(x+6)(x-3)
so we have double zero at x = -6 (graph comes up from way low and bounces back down off the x axis)

Then it comes back up again and goes positive at x = 3

SO
x^3+9x^2 -108 </= 0 for
x<+3