The sum of the squares of the roots of |x-2|2 + |x-2| - 2 = 0 and the squares of the roots of x2 - 2|x-3| - 5 = 0, is
- 24
- 26
- 36
- 30
Answer
(3) 36
Solution
In the first equation, let t = |x - 2| 0; then
t2 + t - 2 = 0 (t + 2)(t - 1) = 0 t = 1
so x = 1, 3 and the sum of squares = 1 + 9 = 10.
In the second equation, for x 3: x2 - 2x + 1 = 0 x = 1, which is rejected since 1 < 3; for x < 3: x2 + 2x - 11 = 0 x = -1 2 3, both less than 3, so both are accepted.
Their sum of squares = (x1 + x2)2 - 2x1x2 = 4 + 22 = 26
Required sum = 10 + 26 = 36
Answer: (3)