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Find the roots of the following quadratic equations by the factorisation method:
$ 21 x^{2}-2 x+\frac{1}{21}=0 $
Given:
Given quadratic equation is \( 21 x^{2}-2 x+\frac{1}{21}=0 \).
To do:
We have to find the roots of the given quadratic equation.
Solution:
\( 21 x^{2}-2 x+\frac{1}{21}=0 \)
Multiplying by 21 on both sides, we get,
$441 x^{2}-42 x+1=0$
$441 x^{2}-(21 x+21 x)+1=0$
$441 x^{2}-21 x-21 x+1=0$
$21 x(21 x-1)-1(21 x-1)=0$
$(21 x-1)(21 x-1)=0$
$21 x-1=0$ or $21 x-1=0$
$x=\frac{1}{21}$ or $x=\frac{1}{21}$
Hence, the roots of the given quadratic equation are $\frac{1}{21}, \frac{1}{21}$.
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