Quadratic Inequality: Solving for x | No Quotes

In summary, the conversation discusses a faulty question in a textbook that has multiple options for the solution. However, the given solution of -6≤x≤3 fits none of the options, leading to the conclusion that the question is incorrect. One person suggests that this may be a recurring issue with the textbook, questioning the validity of the material. The others agree that the options are incorrect and the given solution is correct. It is determined that there is likely a typo in either option B or C.
  • #1
icystrike
445
1

Homework Statement


[/B]
As attached

Homework Equations

The Attempt at a Solution


[/B]
The answer is stated as option A.

However, my solution is -6≤x≤3;
I can seems to find an option that fits the solution.
 

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  • #2
I agree. The question is wrong.
 
  • #3
Your solution looks solid. There must be a problem with the question. Just trying values in the options show that you are correct.
7: 49 < 18-21 -- Nope.
-7: 48 < 18+21 -- Nope.
4: 16 < 18-12 -- Nope.
etc.
You can rule out all the options on the page.
 
  • #4
Man, you've been having a string of bad luck with your textbooks containing faulty problems. If the problems are this bad, I wonder if the material is equally flaky?
 
  • #5
Agreed, those options are wrong (and your solution is correct). There's probably a typo in either B or C.
 

Related to Quadratic Inequality: Solving for x | No Quotes

What is a quadratic inequality?

A quadratic inequality is an inequality that contains a quadratic expression. This expression can be written in the form of ax^2 + bx + c, where a, b, and c are constants and x is the variable. The inequality can be solved to find the values of x that make the inequality true.

How do I solve a quadratic inequality for x?

To solve a quadratic inequality for x, follow these steps:

  1. Isolate the quadratic expression on one side of the inequality, with the other side containing only constants.
  2. Factor the quadratic expression if possible.
  3. Determine the critical values, or the values of x that make the quadratic expression equal to 0.
  4. Plot the critical values on a number line and mark whether they are included or excluded in the solution.
  5. Test a value in each region created by the critical values to determine if it satisfies the inequality.

What if the quadratic inequality cannot be factored?

If the quadratic inequality cannot be factored, you can use the quadratic formula to solve for the values of x that make the inequality true. The quadratic formula is x = (-b ± √(b^2 - 4ac)) / 2a.

What are the different types of solutions for a quadratic inequality?

There are three types of solutions for a quadratic inequality:

  • No solution: This means the inequality has no values of x that make it true.
  • One solution: This means the inequality has one value of x that makes it true.
  • Two solutions: This means the inequality has two values of x that make it true. The solutions can be written in the form of an interval on a number line, such as [a, b].

How can I check my solution to a quadratic inequality?

To check your solution to a quadratic inequality, substitute the value of x into the original inequality. If the inequality is true, then your solution is correct. If the inequality is false, then you need to recheck your work.

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