Question
Mathematics Question on Quadratic Equations
If 2x+3x2+2x+7<6,x∈R, then
A
x>11 or x<−23
B
x>11 or x<−1
C
−23<x<−1
D
−1<x<11 or x<−23
Answer
−1<x<11 or x<−23
Explanation
Solution
Given, 2x+3x2+2x+7<6
⇒2x+3x2+2x+7−6<0
⇒2x+3x2−10x−11<0
⇒2x+3(x−11)(x+1)<0
⇒(2x+3)2(x−11)(x+1)(2x+3)<0
⇒(x−11)(x+1)(2x+3)<0
⇒x∈(−∞,−23)∪(−1,11)