Question
Mathematics Question on Complex Numbers and Quadratic Equations
The solution set of the inequation ∣x+4∣x2+6x−7<0 is
A
(−7,1)
B
(−7,−4)
C
(−7,−4)∪(−4,1)
D
(−7,−4)∪(4,1)
Answer
(−7,−4)∪(−4,1)
Explanation
Solution
∣x+4∣x2+6x−7<0
We know that ∣x+4∣>0
⇒x2+6x−7<0 and x=−4
⇒(x+7)(x−1)<0 and x=−4
\Rightarrow x\,\in\,\left(-7,1\right)-\left\\{-4\right\\}
⇒x∈(−7,−4)∪(−4,1)