Wednesday

October 22, 2014

October 22, 2014

Posted by **Rachale** on Wednesday, July 22, 2009 at 11:34pm.

A. (–infinity, 0)

B. (–infinity, 0) U (7, 9)

C. (–infinity, 0) U (9, infinity)

D. (–infinity, 9)

- Algebra -
**MathMate**, Thursday, July 23, 2009 at 12:14amIt is a cubic, with three real zeroes (0,+7 and +9), therefore the graph crosses the x-axis three times.

The coefficicent of the x³ term is positive, so it increases to the right of the largest root (+9) and decreases to the left of the smallest root (0).

This tells us that (-∞,0) is a subset of the solution.

To find the remaining part of the solution, we note that the function is positive between 0 and the next root, and dips below zero again between the last two roots, namely +7 and +9.

Thus the missing interval is (7,9).

Can you take it from here?

- Algebra -
**Rachale**, Thursday, July 23, 2009 at 1:00amBased upon your explanation, I am goin to say the answer is

B(–infinity, 0) U (7, 9)

? Is this correct?

- Algebra -
**MathMate**, Thursday, July 23, 2009 at 7:16amCorrect!

**Answer this Question**

**Related Questions**

MATH - I have been trying to do this problem for a couple of days but i cant ...

Algebra - Solve |9 – 4x| > 7 and write interval notation for the solution set...

Algebra - please check my answers. thanxs! Solve the polynomial inequality and ...

Algebra - Can you please check my answers? Solve the rational inequality and ...

Calculus - Find the horizontal asymptote of f(x)=e^x - x lim x->infinity (e^x...

Inequality - please check my answers. thanxs! Solve the polynomial inequality ...

Rational Inequities - Can you please check my answers? Solve the rational ...

Algebra - f(x)=root sign, and inside that x-2 and g(x)x-7. Which of the ...

Algebra - Given f(x)=rootsignx-2 and g(x) = x-7 what is the domain of the ...

Algebra - Given f(x)=rootsignx-2 and g(x) = x-7 what is the domain of the ...