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If 8, 2 are roots of the equation x^2 + ...

If 8, 2 are roots of the equation` x^2 + ax + beta `and 3, 3 are roots of `x^2 + alpha x + b = 0` then roots of the equation `x^2+ax+b =0` are

A

`8, -1`

B

`-9, 2`

C

`-8, -2`

D

9, 1

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The correct Answer is:
To solve the problem step-by-step, we will use the information given about the roots of the equations and apply the relationships between coefficients and roots. ### Step 1: Identify the first equation and its roots The first equation is given as: \[ x^2 + ax + \beta = 0 \] with roots 8 and 2. Using the relationships for the sum and product of roots: - Sum of roots \( = 8 + 2 = 10 \) - Product of roots \( = 8 \times 2 = 16 \) From Vieta's formulas: - The sum of the roots is equal to \(-a\), so: \[ -a = 10 \implies a = -10 \] - The product of the roots is equal to \(\beta\), so: \[ \beta = 16 \] ### Step 2: Identify the second equation and its roots The second equation is given as: \[ x^2 + \alpha x + b = 0 \] with roots 3 and 3 (a repeated root). Using the relationships for the sum and product of roots: - Sum of roots \( = 3 + 3 = 6 \) - Product of roots \( = 3 \times 3 = 9 \) From Vieta's formulas: - The sum of the roots is equal to \(-\alpha\), so: \[ -\alpha = 6 \implies \alpha = -6 \] - The product of the roots is equal to \(b\), so: \[ b = 9 \] ### Step 3: Form the third equation Now we have: - \(a = -10\) - \(b = 9\) We can substitute these values into the equation: \[ x^2 + ax + b = 0 \] This becomes: \[ x^2 - 10x + 9 = 0 \] ### Step 4: Solve the third equation To find the roots of the equation \(x^2 - 10x + 9 = 0\), we can factor it: \[ x^2 - 10x + 9 = (x - 1)(x - 9) = 0 \] Setting each factor to zero gives us the roots: \[ x - 1 = 0 \implies x = 1 \] \[ x - 9 = 0 \implies x = 9 \] ### Conclusion The roots of the equation \(x^2 + ax + b = 0\) are: \[ \boxed{1 \text{ and } 9} \]
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OBJECTIVE RD SHARMA ENGLISH-QUADRATIC EXPRESSIONS AND EQUATIONS -Exercise
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