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Find the equation whose roots are ...

Find the equation whose roots are
3 times the roots of ` 6x^4 -7x^3 +8x^2 -7x +2=0`

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To find the equation whose roots are three times the roots of the polynomial \(6x^4 - 7x^3 + 8x^2 - 7x + 2 = 0\), we can follow these steps: ### Step 1: Identify the coefficients of the given polynomial The given polynomial is: \[ 6x^4 - 7x^3 + 8x^2 - 7x + 2 = 0 \] From this, we can identify the coefficients: - \(A = 6\) - \(B = -7\) - \(C = 8\) - \(D = -7\) - \(E = 2\) ### Step 2: Use Vieta's formulas to find relationships between the roots Let the roots of the polynomial be \(\alpha, \beta, \gamma, \delta\). According to Vieta's formulas: 1. The sum of the roots: \[ \alpha + \beta + \gamma + \delta = -\frac{B}{A} = -\frac{-7}{6} = \frac{7}{6} \] 2. The sum of the products of the roots taken two at a time: \[ \alpha\beta + \alpha\gamma + \alpha\delta + \beta\gamma + \beta\delta + \gamma\delta = \frac{C}{A} = \frac{8}{6} = \frac{4}{3} \] 3. The sum of the products of the roots taken three at a time: \[ \alpha\beta\gamma + \alpha\beta\delta + \alpha\gamma\delta + \beta\gamma\delta = -\frac{D}{A} = -\frac{-7}{6} = \frac{7}{6} \] 4. The product of the roots: \[ \alpha\beta\gamma\delta = \frac{E}{A} = \frac{2}{6} = \frac{1}{3} \] ### Step 3: Find the new roots The new roots are \(3\alpha, 3\beta, 3\gamma, 3\delta\). We can find the relationships for the new roots: 1. The sum of the new roots: \[ 3(\alpha + \beta + \gamma + \delta) = 3 \cdot \frac{7}{6} = \frac{7}{2} \] 2. The sum of the products of the new roots taken two at a time: \[ 9(\alpha\beta + \alpha\gamma + \alpha\delta + \beta\gamma + \beta\delta + \gamma\delta) = 9 \cdot \frac{4}{3} = 12 \] 3. The sum of the products of the new roots taken three at a time: \[ 27(\alpha\beta\gamma + \alpha\beta\delta + \alpha\gamma\delta + \beta\gamma\delta) = 27 \cdot \frac{7}{6} = \frac{189}{6} = \frac{63}{2} \] 4. The product of the new roots: \[ 81(\alpha\beta\gamma\delta) = 81 \cdot \frac{1}{3} = 27 \] ### Step 4: Form the new polynomial Using the relationships derived from the new roots, we can form the polynomial: \[ x^4 - \left(\frac{7}{2}\right)x^3 + 12x^2 - \left(\frac{63}{2}\right)x + 27 = 0 \] ### Step 5: Clear the fractions To eliminate the fractions, multiply the entire equation by 2: \[ 2x^4 - 7x^3 + 24x^2 - 63x + 54 = 0 \] ### Final Answer The required polynomial whose roots are three times the roots of the original polynomial is: \[ \boxed{2x^4 - 7x^3 + 24x^2 - 63x + 54 = 0} \]
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