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If 3+223 + 2\sqrt23+22​​ and 3−223 - 2\sqrt23−22​​ are the roots of a quadratic equation, then the quadratic equation is: 
Question

If 3+223 + 2\sqrt2​ and 3223 - 2\sqrt2​ are the roots of a quadratic equation, then the quadratic equation is: 

A.

x26x+1=0x^2 - 6x + 1 = 0​​

B.

x26x1=0x^2 - 6x - 1 = 0​​

C.

x2+6x+1=0x^2 + 6x + 1 = 0​​

D.

x2+6x1=0x^2 + 6x - 1 = 0​​

Correct option is A

Given:

The roots of the quadratic equation are:

α=3+22,β=322\alpha = 3 + 2\sqrt{2}, \quad \beta = 3 - 2\sqrt{2}​​

Concept Used:

A quadratic equation with roots α\alphaα and β\betaβ is given by:

x2(α+β)x+αβ=0x^2 - (\alpha + \beta)x + \alpha \beta = 0​​

Solution:

Sum of roots:

α+β=(3+22)+(322)=6\alpha + \beta = (3 + 2\sqrt{2}) + (3 - 2\sqrt{2}) = 6​​

Product of roots:

αβ=(3+22)(322)\alpha \beta = (3 + 2\sqrt{2})(3 - 2\sqrt{2})​​

Using the identity (a+b)(ab)=a2b2:(a + b)(a - b) = a^2 - b^2:​​

αβ=32(22)2=98=1\alpha \beta = 3^2 - (2\sqrt{2})^2 = 9 - 8 = 1​​

The quadratic equation is:

x2(α+β)x+αβ=0x^2 - (\alpha + \beta)x + \alpha \beta = 0​​

x26x+1=0x^2 - 6x + 1 = 0​​

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