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Question

Mathematics Question on Quadratic Equations

If x2+2x+72x+3<6,xR,\frac{x^{2}+2x+7}{2x+3} < 6, x\,\in\,R, then

A

x>11x >11 or x<32x < -\frac{3}{2}

B

x>11x > 11 or x<1x < -1

C

32<x<1 -\frac{3}{2} < x < -1

D

1<x<11 -1 < x < 11 or x<32x < -\frac{3}{2}

Answer

1<x<11 -1 < x < 11 or x<32x < -\frac{3}{2}

Explanation

Solution

Given, x2+2x+72x+3<6\frac{x^{2}+2 x+7}{2 x+3}<6
x2+2x+72x+36<0\Rightarrow \frac{x^{2}+2 x+7}{2 x+3}-6<0
x210x112x+3<0\Rightarrow \frac{x^{2}-10 x-11}{2 x+3}<0
(x11)(x+1)2x+3<0\Rightarrow \frac{(x-11)(x+1)}{2 x+3}<0
(x11)(x+1)(2x+3)(2x+3)2<0\Rightarrow \frac{(x-11)(x+1)(2 x+3)}{(2 x+3)^{2}}<0
(x11)(x+1)(2x+3)<0\Rightarrow (x-11)(x+1)(2 x+3) < 0
x(,32)(1,11)\Rightarrow x \in\left(-\infty,-\frac{3}{2}\right) \cup(-1,11)