Download App

STD 11 - 4.2 Quadratic equations and inequations — Maths STD 11 Science — Question

CBSE BoardEnglish MediumSTD 11 ScienceMathsSTD 11 - 4.2 Quadratic equations and inequations1 Mark
MCQ
Two real numbers $\alpha$ and $\beta $ are such that $\alpha  + \beta  = 3$ and $\left| {\alpha  - \beta } \right| = 4$, then $\alpha$  and  $\beta $  are the roots of the quadratic equation
  • ✓
    $4x^2-12x-7=0$
  • B
    $4x^2-12x+7=0$
  • C
    $4x^2-12x+25=0$
  • D
    none of these
✓

Answer

Correct option: A.
$4x^2-12x-7=0$
a
$\alpha+\beta=3$

also $(\alpha-\beta)^{2}=(\alpha+\beta)^{2}-4 \alpha \beta$

$\Rightarrow \quad \alpha \beta=-\frac{7}{4}$

required quadratic equation is

$  x^{2}-x(3)-\frac{7}{4}=0 $

$ \Rightarrow  4 x^{2}-12 x-7=0$

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 STD 11 - 4.2 Quadratic equations and inequations→STD 11 - 4.2 Quadratic equations and inequations — all question types→Maths STD 11 Science question papers→CBSE Board STD 11 Science question papers→CBSE Board question paper generator→

Similar questions

If the line $y$ $\cos \alpha = x\sin \alpha + a\cos \alpha $ be a tangent to the circle ${x^2} + {y^2} = {a^2}$, then
→
If $n = 1,2,3, ...,$ then $\cos\alpha\cos4\alpha\ ...\cos2^{\text{n}-1}\alpha$ is equal to:
→
If the quadratic equation ${x^2} + \left( {2 - \tan \theta } \right)x - \left( {1 + \tan \theta } \right) = 0$ has $2$ integral roots, then sum of all possible values of $\theta $ in interval $(0, 2\pi )$ is $k\pi $, then $k$ equals 
→
If $\text{L}=\lim\limits_{\text{x}\rightarrow0}\frac{\text{a}\sin\text{x}-\sin^2\text{x}}{\tan^3\text{x}}$ is finite, then the value of $L$ is:
→
The set $A = \{ x:x \in R,\,{x^2} = 16$ and $2x = 6\} $ equals
→
The number of terms with integral coefficients in the expansion of $\Big(7^{\frac{1}{3}}+5^{\frac{1}{2}}\cdot\text{x}\Big)^{600}$ is:
→
A triangle is formed by the tangents at the point $(2,2)$ on the curves $y^2=2 x$ and $x^2+y^2=4 x$, and the line $x+y+2=0$. If $r$ is the radius of its circumcircle, then $r ^2$ is equal to $........$.
→
If the middle term of $\big(\frac{1}{\text{x}}+\text{x}\sin\text{x}\big)10$ is equal to $7.\frac{7}{8},$ then value of $x$ is:
→
If focus and directrix of a parabola are $(3, 5)$ and $x + y = 4$ , then coordinates of its vertex are
→
If $\tan\alpha=\frac{1}{7},\tan\beta=-\frac{1}{3},$ then $\cos2\alpha$ is equal to:
→