Need help solving these problems

-√3/7
(4√12)(3√20)
√2+√8+√50

1. i don't understand your first expression: -\sqrt {\frac37} or -\frac {\sqrt 3}{7}

2. (4sqrt12)(3sqrt20) = (4*3)(sqrt{12*20}) = 12sqrt{240} Can simplify from here?

3. sqrt2 + sqrt8 + sqrt{50}=sqrt2 + 2sqrt2 + 5sqrt2 Can simplify from here?