Download App

Complex Numbers and Quadratic Equations — Maths STD 11 Science — Question

CBSE BoardEnglish MediumSTD 11 ScienceMathsComplex Numbers and Quadratic Equations1 Mark
MCQ
The values of $x$ satisfying $\log_3 (x^2+ 4x + 12) = 2$ are:
  • A
    $2, −4$
  • B
    $1, −3$
  • C
    $−1, 3$
  • ✓
    $−1, −3$
✓

Answer

Correct option: D.
$−1, −3$
The given equation is $\log_3(x^2 + 4x + 12) = 2$
$\Rightarrow x^2 + 4x + 12 = 3^2= 9$
$\Rightarrow x^2 + 4x + 3 = 0$
$\Rightarrow (x + 1) (x + 3) = 0$
$\Rightarrow x = -1, -3$

Need a full question paper?

Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.

Start Generating Free

Explore more

More "M.C.Q (1 Marks)" from Complex Numbers and Quadratic Equations→Complex Numbers and Quadratic Equations — all question types→Maths STD 11 Science question papers→CBSE Board STD 11 Science question papers→CBSE Board question paper generator→

Similar questions

The number of rectangles that can be obtained by joining four of the twelve vertices of a $12$ -sided regular polygon is
→
Choose the correct answer. If the third term of $\text{G.P.}$ is $4,$ then the product of its first $5$ terms is:
→
If $A, B$ and $C$ are any three set, then $\ce{A ∪ (B ∩ C):}$
→
If $\sin ^{2}\left(10^{\circ}\right) \sin \left(20^{\circ}\right) \sin \left(40^{\circ}\right) \sin \left(50^{\circ}\right) \sin \left(70^{\circ}\right)=\alpha-$ $\frac{1}{16} \sin \left(10^{\circ}\right)$, then $16+\alpha^{-1}$ is equal to
→
The number of permutations of the letters $a_1, a_2, a_3, a_4, a_5$ in which the first letter $a_1$ does not occupy the first position (from the left) and the second letter $a_2$ does not occupy the second position (from the left) is
→
If $19^{th}$ terms of non -zero $A.P.$ is zero, then its ($49^{th}$ term) : ($29^{th}$ term) is
→
If $\text{i}^2=-1,$ then the sum $\text{i}+\text{i}^2+\text{i}^3+...$ upto 1000 terms is equal to:
→
An organization awarded $48$ medals in event '$A$',$25$ in event '$B$ ' and $18$ in event ' $C$ '. If these medals went to total $60$ men and only five men got medals in all the three events, then, how many received medals in exactly two of three events?
→
The argument of the complex number $\sin \,\frac{{6\pi }}{5}\, + \,i\,\left( {1\, + \,\cos \,\frac{{6\pi }}{5}} \right)$ is 
→
$|{z_1} + {z_2}|\, = \,|{z_1}| + |{z_2}|$ is possible if
→