The number of distinct real solutions of the equation x|x+4| + 3|x+2| + 10 = 0 is
- 2
- 3
- 0
- 1
Answer
(4) 1
Solution
Case 1: x -2
x(x+4) + 3(x+2) + 10 = 0 x2 + 7x + 16 = 0
D = 49 - 64 < 0 no real root.
Case 2: -4 x < -2
x(x+4) - 3(x+2) + 10 = 0 x2 + x + 4 = 0
D = 1 - 16 < 0 no real root.
Case 3: x < -4
-x(x+4) - 3(x+2) + 10 = 0 x2 + 7x - 4 = 0
x = -7 652
x = -7 - 652 -7.53 (accepted, < -4); x = -7 + 652 0.53 (rejected)
Number of distinct real solutions = 1
Answer: (4)