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If r and s are the roots of x2−3x+2=0x^2 - 3x + 2 = 0x2−3x+2=0​, then the quadratic equation in x whose roots are r2+s2r^2 + s^2r2+s2 and (rs)2(rs)^2
Question

If r and s are the roots of x23x+2=0x^2 - 3x + 2 = 0​, then the quadratic equation in x whose roots are r2+s2r^2 + s^2 and (rs)2(rs)^2 is:

A.

x2+9x20=0x^2 + 9x - 20 = 0​​

B.

x2+9x+20=0x^2 + 9x + 20 = 0​​

C.

x29x+20=0x^2 - 9x + 20 = 0​​

D.

x29x20=0x^2 - 9x - 20 = 0​​

Correct option is C

Given:

If r and s are roots of given equation =x23x+2=0x^2 - 3x + 2 = 0​​

Formula Used:

For finding the roots we use:

Quadratic formula :x=b±b24ac2ax =\frac{ -b \pm \sqrt{b^2 - 4ac}}{2a}​​

If α\alpha​ and β\beta​ are roots of a equation:

Then equation is given by : x2(α+β)x+(αβ)=0x^2 - (\alpha + \beta)x + (\alpha\beta) = 0​​

Solution:

x=b±b24ac2ax =\frac{ -b \pm \sqrt{b^2 - 4ac}}{2a}​​

=(3)±(3)24(1)(2)2(1)=\frac{ -(-3) \pm \sqrt{(-3)^2 - 4(1)(2)}}{2(1)}​​

=3±982=\frac{ 3 \pm \sqrt{9 - 8}}{2}​​

x=3+12orx=312x= \frac{3+1}{2} or x =\frac{3-1}{2}​​

r= 2 and s= 1

α=r2+s2=(2)2+(1)2=4+1=5\alpha = r^2 + s^2 = (2)^2 + (1)^2 = 4+1 = 5​​

β=(rs)2=(2×1)2=4\beta = (rs)^2= (2\times 1)^2 = 4​​

Quadratic equation = x2(5+4)x+(5)(4)=0x^2 - (5+4)x + (5)(4) =0​​

x29x+20=0x^2 - 9x +20 = 0​​

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