Show the following quadratic equation by factorization method: 21… - Vidyadip

Question

Show the following quadratic equation by factorization method:
$21x^2 - 28x + 10 = 0$

✓

Answer

$21x^2 - 28x + 10 = 0$
We will apply discriminant rule,
$\text{x}=\frac{-\text{b}\pm\sqrt{\text{D}}}{2\text{a}}\ ...(\text{A})$
Where $D = b^2 - 4ac$
$= (-28)^2 - 4.21.10$
$= 784 - 840$
$= -56$
From $(A)$
$\text{x}=\frac{-28\pm\sqrt{-56}}{2.21}$
$=\frac{-28\pm2\sqrt{14}\text{ i}}{42}$
$\therefore\text{x}=\frac{2}{3}\pm\frac{\sqrt{14}}{21}\ \text{i}$

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 "3 Marks Question" from Quadratic Equations→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

Find the general solutions of the following equations:
$\sin2\text{x}+\cos\text{x}=0$

Find the equation of the line passing through the intersection of the lines 2x + y = 5 and x + 3y + 8 = 0 and parallel to the line 3x + 4y = 7.

If the lines $2x - 3y = 5$ and $3x - 4y = 7$ are the diameters of a circle of area $154$ square units, then obtain the equation of the circle.

Let sum of $n, 2n, 3n$ terms of an A.P. be $S_1, S_2$_ and $S_3$_respectively, show that $S_3 = 3(S_2 - S_1).$

In a class, $18$ students took Physics $, 23$ students took Chemistry and $24$ students took
Mathematics of these $13$ took both Chemistry and Mathematics, $12$ took both Physics and Chemistry and $11$ took both Physics an Mathematics. If $6$ students offered all the three subjects, find:
$i$. The total number of students.
$ii$. How many took Maths but not Chemistry.
$iii$. How many took exactly one of the three subjects.

Solve the following system of linear inequations:
$3 x-6 \geq 0$
$4 x-10 \leq 6$

A man saved Rs. 66000 in 20 years. In each succeeding year after the first year he saved Rs. 200 more than what he saved in the previous year. How much did he save in the first year?

Solve the following system of equations in R.
$-5<2\text{x}-3<5$

If $\alpha $ and $\beta $ are different complex numbers with $\left| \beta \right| = 1$ then find $\left| {\frac{{\beta - \alpha }}{{1 - \overline \alpha \beta }}} \right|$

How many three digit numbers can be formed by using the digits 0, 1, 3, 5, 7 while each digit may be repeated any number of times?