Apply the Fundamental Theorem of Algebra to find the number of roots for the equation 12x−6x2+3x4=6x3+2x−x4

12
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6
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2
+
3
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4
=
6
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3
+
2
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4

1 answer

To apply the Fundamental Theorem of Algebra to the equation, we first need to simplify and rearrange it into a standard polynomial form. The given equation is:

\[ 12x - 6x^2 + 3x^4 = 6x^3 + 2x - x^4 \]

First, let's move all terms to one side of the equation:

\[ 3x^4 + x^4 - 6x^3 - 6x^2 + 12x - 2x = 0 \]

Combining like terms gives:

\[ (3x^4 + x^4) - 6x^3 - 6x^2 + (12x - 2x) = 0 \]

\[ 4x^4 - 6x^3 - 6x^2 + 10x = 0 \]

Now, we can factor out the greatest common factor from the left-hand side:

\[ 2x(2x^3 - 3x^2 - 3x + 5) = 0 \]

Setting \(2x = 0\) gives us one root:

\[ x = 0 \]

Now we need to find the roots of the cubic polynomial \(2x^3 - 3x^2 - 3x + 5 = 0\).

The Fundamental Theorem of Algebra states that a polynomial of degree \(n\) has exactly \(n\) roots (counting multiplicities) in the complex numbers. The cubic polynomial has a degree of 3, which means it will have 3 roots in total.

Combining both parts, we have:

  • One root from \(2x = 0\): \(x = 0\)
  • Three roots from the cubic polynomial \(2x^3 - 3x^2 - 3x + 5 = 0\)

Thus, the total number of roots for the equation \(12x - 6x^2 + 3x^4 = 6x^3 + 2x - x^4\) is:

\[ 1 + 3 = 4 \]

Therefore, the equation has 4 roots in total, counting multiplicities.