\(-4\sqrt{3}\)
\(\frac{-4\sqrt{3}}{3}\)
\(\frac{-3\sqrt{3}}{4}\)
\(\frac{-3\sqrt{3}}{4}\)
Correct answer is B
\(a \Delta b\) = \(\frac{a+b}{\sqrt{ab}}\)
\(-3\Delta -1\) = \(\frac{-3 + -1}{\sqrt{-3\times -1}}\)
\(\frac{-4}{\sqrt{3}}\), rationalising, we have
\(\frac{-4 \times \sqrt{3}}{\sqrt{3}\times \sqrt{3}} = \frac{-4\sqrt{3}}{3}\)