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Let 'm' be a real number, and suppose th...

Let `'m'` be a real number, and suppose that two of the three solutions of the cubic equation `x^(3)+3x^(2)-34x=m` differ by `1`. Then possible value of `'m'` is/are

A

(a) `120`

B

(b) `80`

C

(c) `-48`

D

(d) `-32`

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To solve the problem, we start with the cubic equation: \[ x^3 + 3x^2 - 34x = m \] We know that two of the roots of this equation differ by 1. Let's denote these roots as \( a \) and \( a + 1 \). The third root will be denoted as \( b \). ### Step 1: Set up the equations for the roots Since \( a \) and \( a + 1 \) are roots, we can substitute them into the cubic equation: 1. For \( x = a \): \[ a^3 + 3a^2 - 34a = m \tag{1} \] 2. For \( x = a + 1 \): \[ (a + 1)^3 + 3(a + 1)^2 - 34(a + 1) = m \tag{2} \] ### Step 2: Expand equation (2) Now, we expand equation (2): \[ (a + 1)^3 = a^3 + 3a^2 + 3a + 1 \] \[ 3(a + 1)^2 = 3(a^2 + 2a + 1) = 3a^2 + 6a + 3 \] \[ -34(a + 1) = -34a - 34 \] Combining these, we have: \[ m = a^3 + 3a^2 + 3a + 1 + 3a^2 + 6a + 3 - 34a - 34 \] \[ = a^3 + 6a^2 - 25a - 30 \tag{3} \] ### Step 3: Set equations (1) and (3) equal to each other Since both equations equal \( m \), we can set them equal to each other: \[ a^3 + 3a^2 - 34a = a^3 + 6a^2 - 25a - 30 \] ### Step 4: Simplify the equation Subtract \( a^3 \) from both sides: \[ 3a^2 - 34a = 6a^2 - 25a - 30 \] Rearranging gives: \[ 0 = 6a^2 - 25a - 30 - 3a^2 + 34a \] \[ 0 = 3a^2 + 9a - 30 \] ### Step 5: Factor the quadratic equation We can factor out a 3: \[ 0 = a^2 + 3a - 10 \] This can be factored as: \[ 0 = (a - 2)(a + 5) \] ### Step 6: Solve for \( a \) Setting each factor to zero gives us the possible values for \( a \): 1. \( a - 2 = 0 \) → \( a = 2 \) 2. \( a + 5 = 0 \) → \( a = -5 \) ### Step 7: Find the corresponding values of \( m \) Now we substitute these values of \( a \) back into equation (1) to find \( m \). 1. For \( a = 2 \): \[ m = 2^3 + 3(2^2) - 34(2) \] \[ = 8 + 12 - 68 = -48 \] 2. For \( a = -5 \): \[ m = (-5)^3 + 3(-5)^2 - 34(-5) \] \[ = -125 + 75 + 170 = 120 \] ### Conclusion The possible values of \( m \) are: \[ m = -48 \quad \text{and} \quad m = 120 \]

To solve the problem, we start with the cubic equation: \[ x^3 + 3x^2 - 34x = m \] We know that two of the roots of this equation differ by 1. Let's denote these roots as \( a \) and \( a + 1 \). The third root will be denoted as \( b \). ### Step 1: Set up the equations for the roots ...
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