simplify the expression

Hey there!

Is any of this question cut off? I am not getting any of these 4 answer?

EDIT: nevermind, i'm dumb, give me minute...

Here we want to multiply the fraction by its conjugate, thus:

\(\frac{10\sqrt{7}}{-1+\sqrt{10}} \times \frac{1+\sqrt{10}}{1+\sqrt{10}}=\frac{10\sqrt{7}(1+\sqrt{10}}{(-1+\sqrt{10})(1+\sqrt{10})}\)

expanding the denomenator comes out as 9. after expanding we get the following

\(\frac{10\sqrt{7}+10\sqrt{70}}{9}=\frac{-10\sqrt{7}-10\sqrt{70}}{-9}\)

I hope this helped :)