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Obtain all zeros of (3x^4 -15x^3 + 13x^2...

Obtain all zeros of `(3x^4 -15x^3 + 13x^2 +25x -30)`, if two of its zeros are`sqrt(5/3) and - sqrt(5/3)`.

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To find all the zeros of the polynomial \( p(x) = 3x^4 - 15x^3 + 13x^2 + 25x - 30 \), given that two of its zeros are \( \sqrt{\frac{5}{3}} \) and \( -\sqrt{\frac{5}{3}} \), we can follow these steps: ### Step 1: Form a quadratic factor from the known zeros Since we know two of the zeros, we can express them as factors: \[ (x - \sqrt{\frac{5}{3}})(x + \sqrt{\frac{5}{3}}) = x^2 - \left(\sqrt{\frac{5}{3}}\right)^2 = x^2 - \frac{5}{3} \] To eliminate the fraction, we can multiply the entire factor by 3: \[ 3(x^2 - \frac{5}{3}) = 3x^2 - 5 \] So, we have one factor of the polynomial: \[ d(x) = 3x^2 - 5 \] ### Step 2: Use polynomial long division Now we will divide the original polynomial \( p(x) \) by \( d(x) \): \[ p(x) = 3x^4 - 15x^3 + 13x^2 + 25x - 30 \] We will divide by \( 3x^2 - 5 \). 1. Divide the leading term: \( \frac{3x^4}{3x^2} = x^2 \). 2. Multiply \( x^2 \) by \( 3x^2 - 5 \): \[ x^2(3x^2 - 5) = 3x^4 - 5x^2 \] 3. Subtract this from \( p(x) \): \[ (3x^4 - 15x^3 + 13x^2 + 25x - 30) - (3x^4 - 5x^2) = -15x^3 + 18x^2 + 25x - 30 \] 4. Repeat the process: Divide the leading term \( \frac{-15x^3}{3x^2} = -5x \). 5. Multiply \( -5x \) by \( 3x^2 - 5 \): \[ -5x(3x^2 - 5) = -15x^3 + 25x \] 6. Subtract: \[ (-15x^3 + 18x^2 + 25x - 30) - (-15x^3 + 25x) = 18x^2 - 30 \] 7. Divide again: \( \frac{18x^2}{3x^2} = 6 \). 8. Multiply \( 6 \) by \( 3x^2 - 5 \): \[ 6(3x^2 - 5) = 18x^2 - 30 \] 9. Subtract: \[ (18x^2 - 30) - (18x^2 - 30) = 0 \] So, we have \( p(x) = (3x^2 - 5)(x^2 - 5x + 6) \). ### Step 3: Factor the quadratic \( x^2 - 5x + 6 \) Now we need to factor \( x^2 - 5x + 6 \): \[ x^2 - 5x + 6 = (x - 2)(x - 3) \] ### Step 4: Find all zeros Now we can write the complete factorization of \( p(x) \): \[ p(x) = (3x^2 - 5)(x - 2)(x - 3) \] Setting each factor to zero gives us the zeros: 1. From \( 3x^2 - 5 = 0 \): \[ 3x^2 = 5 \implies x^2 = \frac{5}{3} \implies x = \pm \sqrt{\frac{5}{3}} \] 2. From \( x - 2 = 0 \): \[ x = 2 \] 3. From \( x - 3 = 0 \): \[ x = 3 \] ### Final Answer The zeros of the polynomial \( p(x) \) are: \[ \sqrt{\frac{5}{3}}, -\sqrt{\frac{5}{3}}, 2, 3 \]

To find all the zeros of the polynomial \( p(x) = 3x^4 - 15x^3 + 13x^2 + 25x - 30 \), given that two of its zeros are \( \sqrt{\frac{5}{3}} \) and \( -\sqrt{\frac{5}{3}} \), we can follow these steps: ### Step 1: Form a quadratic factor from the known zeros Since we know two of the zeros, we can express them as factors: \[ (x - \sqrt{\frac{5}{3}})(x + \sqrt{\frac{5}{3}}) = x^2 - \left(\sqrt{\frac{5}{3}}\right)^2 = x^2 - \frac{5}{3} \] To eliminate the fraction, we can multiply the entire factor by 3: ...
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NAGEEN PRAKASHAN ENGLISH-POLYNOMIALS-Exercise 2b
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