Question:
Solve each of the following quadratic equations:
$x^{2}+3 \sqrt{3} x-30=0$
Solution:
We write, $3 \sqrt{3} x=5 \sqrt{3} x-2 \sqrt{3} x$ as $x^{2} \times(-30)=-30 x^{2}=5 \sqrt{3} x \times(-2 \sqrt{3} x)$
$\therefore x^{2}+3 \sqrt{3} x-30=0$
$\Rightarrow x^{2}+5 \sqrt{3} x-2 \sqrt{3} x-30=0$
$\Rightarrow x(x+5 \sqrt{3})-2 \sqrt{3}(x+5 \sqrt{3})=0$
$\Rightarrow(x+5 \sqrt{3})(x-2 \sqrt{3})=0$
$\Rightarrow x+5 \sqrt{3}=0$ or $x-2 \sqrt{3}=0$
$\Rightarrow x=-5 \sqrt{3}$ or $x=2 \sqrt{3}$
Hence, the roots of the given equation are $-5 \sqrt{3}$ and $2 \sqrt{3}$.