Question
Question: Sum of all the values of m for which the roots x<sub>1</sub> and x<sub>2</sub> of the quadratic equa...
Sum of all the values of m for which the roots x1 and x2 of the quadratic equation x2 – 2mx + m = 0 satisfy the condition x13 + x23 = x12 + x22, is –
A
43
B
1
C
49
D
45
Answer
45
Explanation
Solution
x1 + x2 = 2m, x1x2 = m
x13 + x23 = (x1 + x2)3 – 3x1x2 (x1 + x2)
= 8m3 – 3m(2m)
x12 + x22 = (x1 + x2)2 – 2x1x2 = 4m2 – 2m
8m3 – 6m2 = 4m2 – 2m
Ž 8m3 – 10 m2 + 2m = 0
Sum of values = 810 = 45.