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Quadratic equation

Maths & Stats

Find the quadratic equation sum of whose roots is 3 and the sum of cubes of roots is 7

DIVYA S

CA Final

★ 52K+

25-Feb-20 12:25

478

Answers (3)

2,-1

rishi pandey

CA Foundation

★ 1K+

25-Feb-20 19:14

rishi pandey

2,-1

How

Chinna Sai

CA Inter

★ 7K+

26-Apr-20 07:36

Let roots be a & b; a + b = 3; (a)3 +(b)3 = 7 (a+b)3 = a3 +b3 +3ab(a+b) (a+b)3 = 7 + 3ab( 3) (3)3 = 7 + 9ab 9ab = 20 ab = 20/9 a+b = 3 A quadratic equation is xÂ² - (sum of roots) x + product of roots= 0 xÂ² - 3x + Â 20/9 = 0 9xÂ² -27x + Â 20 = 0