Find the zeros: Includes a cube

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In summary, the conversation discusses finding the zeros of the function f(x) = 4x^3 - 24x^2 - x + 6 algebraically. The attempt at a solution involves factoring the function and setting each factor equal to zero to find the roots. The conversation concludes with the correct answer being 6, +1/2, and -1/2 and a suggestion to check the values by plugging them into the original function.
  • #1
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Homework Statement



Find the zeros of the function algebraically.

Homework Equations



f(x) = 4x^3 - 24x^2 - x + 6

The Attempt at a Solution



If all quantities had an x in them, I'd just factor out and x, and treat it as a quadratic. But that freaking 6 is ruining my plan and I'm stuck.
 
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  • #2
You'll have to try and factor it. Look for a rational root.
 
  • #3
k, so I factored it to (1 - 4x^2)(-x - 6)

...what are the zeros? 6? Someone help me interpret that...pleeease.
 
  • #4
How did you get the (-x-6) factor? I get just (x-6). Or did you mean to write (-x+6)? Then to find the roots, just set each factor equal to zero, right? The product of things can only be zero if one of the things is zero.
 
  • #5
Damnit, yeah I meant to have (x - 6).
 
  • #6
Okay so they're 6, +1/2, -1/2. Correct if I'm wrong. If not, thanks.
 
  • #7
They are correct. Didn't want to just leave you hanging. You can also check for yourself, just put those values into the polynomial and see if you get zero.
 

Related to Find the zeros: Includes a cube

What is the significance of finding the zeros of a cubic equation?

Finding the zeros of a cubic equation allows us to determine the points where the graph of the equation crosses the x-axis. These points represent the roots or solutions of the equation and can provide valuable information about the behavior of the equation.

How do you find the zeros of a cubic equation?

The most common method for finding the zeros of a cubic equation is by using the cubic formula. This formula involves taking the coefficients of the equation and plugging them into a formula to find the roots. Another method is by factoring the equation and using the zero product property.

What are the possible number of zeros for a cubic equation?

A cubic equation can have up to three real or complex zeros. This is based on the fundamental theorem of algebra, which states that a polynomial of degree n has n complex roots.

How do you solve for complex zeros of a cubic equation?

To find complex zeros of a cubic equation, we can use the complex conjugate root theorem. This states that if a polynomial with real coefficients has a complex root, then its conjugate is also a root. By using this theorem, we can simplify the equation and solve for the complex roots.

What are some real-world applications of finding the zeros of a cubic equation?

Finding the zeros of a cubic equation has many real-world applications, such as in physics and engineering. It can be used to model the behavior of objects in motion, determine optimal solutions in economics, and solve problems in chemistry and biology. Additionally, finding the zeros can help us understand the behavior of natural phenomena, such as population growth or the spread of diseases.

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