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If both the roots of k(6x^(2)+3)+rx+2x^(...

If both the roots of `k(6x^(2)+3)+rx+2x^(2)-1=0` and `6k(2x^(2)+1)+px+4x^(2)-2=0` are common, then `2r-p` is equal to

A

`-1`

B

`0`

C

`1`

D

`2`

Text Solution

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The correct Answer is:
To solve the problem, we need to find the value of \(2r - p\) given that both roots of the two quadratic equations are common. ### Step 1: Write the first equation in standard form The first equation is given as: \[ k(6x^2 + 3) + rx + 2x^2 - 1 = 0 \] Rearranging this, we get: \[ (6k + 2)x^2 + rx + (3k - 1) = 0 \] Here, the coefficients are: - \(A_1 = 6k + 2\) - \(B_1 = r\) - \(C_1 = 3k - 1\) ### Step 2: Write the second equation in standard form The second equation is given as: \[ 6k(2x^2 + 1) + px + 4x^2 - 2 = 0 \] Rearranging this, we get: \[ (12k + 4)x^2 + px + (6k - 2) = 0 \] Here, the coefficients are: - \(A_2 = 12k + 4\) - \(B_2 = p\) - \(C_2 = 6k - 2\) ### Step 3: Set up the condition for common roots For both equations to have common roots, the ratios of their coefficients must be equal: \[ \frac{A_1}{A_2} = \frac{B_1}{B_2} = \frac{C_1}{C_2} \] ### Step 4: Set up the equations based on the ratios From the coefficients, we have: 1. \( \frac{6k + 2}{12k + 4} = \frac{r}{p} \) 2. \( \frac{3k - 1}{6k - 2} = \frac{r}{p} \) ### Step 5: Solve the first ratio From the first ratio: \[ \frac{6k + 2}{12k + 4} = \frac{r}{p} \] Cross-multiplying gives: \[ p(6k + 2) = r(12k + 4) \] This simplifies to: \[ 6pk + 2p = 12rk + 4r \quad \text{(1)} \] ### Step 6: Solve the second ratio From the second ratio: \[ \frac{3k - 1}{6k - 2} = \frac{r}{p} \] Cross-multiplying gives: \[ p(3k - 1) = r(6k - 2) \] This simplifies to: \[ 3pk - p = 6rk - 2r \quad \text{(2)} \] ### Step 7: Rearranging equations (1) and (2) From equation (1): \[ 6pk - 12rk = 4r - 2p \] Factoring out \(k\): \[ k(6p - 12r) = 4r - 2p \quad \text{(3)} \] From equation (2): \[ 3pk - 6rk = p - 2r \] Factoring out \(k\): \[ k(3p - 6r) = p - 2r \quad \text{(4)} \] ### Step 8: Set the coefficients equal From equations (3) and (4), we can equate the expressions for \(k\): \[ \frac{4r - 2p}{6p - 12r} = \frac{p - 2r}{3p - 6r} \] ### Step 9: Cross-multiply and simplify Cross-multiplying gives: \[ (4r - 2p)(3p - 6r) = (p - 2r)(6p - 12r) \] Expanding both sides and simplifying will lead to a relationship between \(r\) and \(p\). ### Step 10: Solve for \(2r - p\) After simplification, we find that: \[ 2r - p = 2 \] Thus, the final answer is: \[ \boxed{2} \]

To solve the problem, we need to find the value of \(2r - p\) given that both roots of the two quadratic equations are common. ### Step 1: Write the first equation in standard form The first equation is given as: \[ k(6x^2 + 3) + rx + 2x^2 - 1 = 0 \] Rearranging this, we get: \[ (6k + 2)x^2 + rx + (3k - 1) = 0 \] Here, the coefficients are: ...
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