Find the roots of the following quadratic equations (if they exist) by the method of completing the square.
$4 x^{2}+4 \sqrt{3} x+3=0$
We have been given that,
$4 x^{2}+4 \sqrt{3} x+3=0$
Now divide throughout by 4. We get,
$x^{2}+\sqrt{3} x+\frac{3}{4}=0$
Now take the constant term to the RHS and we get
$x^{2}+\sqrt{3} x=-\frac{3}{4}$
Now add square of half of co-efficient of ‘x’ on both the sides. We have,
$x^{2}+2\left(\frac{\sqrt{3}}{2}\right) x+\left(\frac{\sqrt{3}}{2}\right)^{2}=\left(\frac{\sqrt{3}}{2}\right)^{2}-\frac{3}{4}$
$x^{2}+2\left(\frac{\sqrt{3}}{2}\right) x+\left(\frac{\sqrt{3}}{2}\right)^{2}=0$
$\left(x+\frac{\sqrt{3}}{2}\right)^{2}=0$
Since RHS is a positive number, therefore the roots of the equation exist.
So, now take the square root on both the sides and we get
$x+\frac{\sqrt{3}}{2}=0$
$x=-\frac{\sqrt{3}}{2}$
Now, we have the values of ‘x’ as
$x=-\frac{\sqrt{3}}{2}$
Also we have,
$x=-\frac{\sqrt{3}}{2}$
Therefore the roots of the equation are $-\frac{\sqrt{3}}{2}$ and $-\frac{\sqrt{3}}{2}$.