Q8 of 227 Page 114

If α and β are roots of 3x2 – 6x + 1 = 0, then form a quadratic equation whose roots are

(i) (ii) α2β, β2α (iii) 2α + β, 2β + α

3x2 – 6x + 1 = 0 compare this with ax2 – bx + c = 0


a = 3 , b = –6 and c = 1








i). Here


General form of quadratic equation whose roots are α2 and β2






x2 – 6x + 3 = 0


Therefore, required equation is x2 – 6x + 3 = 0


ii). Here, α = α2β and β = β2 α


General form of quadratic equation whose roots are α2β and β2 α


x2 – (α2β + β2 α) x + (α2β)(β2 α) = 0


x2 – αβ (α + β) x + (α3β3) = 0


x2 – αβ (α + β) x + (αβ)3 = 0





27x2 – 18x + 1 = 0


Therefore, required equation is 27x2 – 18x + 1 = 0


iii). Here, α = 2α + β and β = 2β + α


General form of equation whose roots are 2α + β and 2β + α


x2 – (2α + β + 2β + α)x + (2α + β)(2β + α) = 0


x2 – (3α + 3β) x + (4αβ + 2α2 + 2β2 + αβ) = 0


x2 – (3α + 3β) x + (2(α2 + β2 ) + 5αβ) = 0


α2 + β2 = (α + β)2 – 2αβ





x2 – (3α + 3β) x + (2(α2 + β2 ) + 5αβ) = 0






3x2 –18x + 70 = 0


Therefore, the required equation is 3x2 –18x + 70 = 0


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