Tuesday, October 29, 2013

inequality



Solve the inequality: x2(3 – x)(x – 2)2(x + 4)3 > 0
 
Answer:
The LHS can be rewritten as {x(x – 2)(x + 4)}2(3 – x)(x + 4) > 0
Now since, {x(x – 2)(x + 4)}2 > 0
Therefore, the inequality boils down to proving (3 – x)(x + 4) > 0
This condition can be satisfied under 2 conditions, namely;
Condition 1
(3 – x) > 0
(x + 4) > 0
ð  X < 3
ð  X > - 4
ð  -4 < x < 3
Condition 2
(3 – x) < 0
(x + 4) < 0
ð  X > 3
ð  X < - 4
ð  These values  do not satisfy the condition
So, the answer is -4 < x < 3

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