SOLUTION: In 18x^3 + 24x^2 + 8x >= 0 (solved in interval notation), why is [-2/3] on it's own with the correct answer being [-2/3]U[0,infinity)? Rather than (-infinity,-2/3]U[0,infinity)?

Algebra ->  Inequalities -> SOLUTION: In 18x^3 + 24x^2 + 8x >= 0 (solved in interval notation), why is [-2/3] on it's own with the correct answer being [-2/3]U[0,infinity)? Rather than (-infinity,-2/3]U[0,infinity)?      Log On


   

Question 1010053: In 18x^3 + 24x^2 + 8x >= 0 (solved in interval notation), why is [-2/3] on it's own with the correct answer being [-2/3]U[0,infinity)? Rather than (-infinity,-2/3]U[0,infinity)?
Answer by MathLover1(20849) About Me  (Show Source):
You can put this solution on YOUR website!

18x%5E3+%2B+24x%5E2+%2B+8x+%3E=+0

as you can see 18x%5E3+%2B+24x%5E2+%2B+8x must be >= 0
so, for that reason you cannot use interval (-infinity,-2%2F3]U[0,infinity)
solutions are: x%3E=0 and x+=+-2%2F3
and interval solution is:
[-2%2F3]U[0,infinity)