\(\frac{3-\sqrt{3}}{\sqrt{3}-1}+\frac{\sqrt{35}-\sqrt{15}}{\sqrt{5}}-\sqrt{28}\)
\(=\frac{\left(3-\sqrt{3}\right)\left(\sqrt{3}+1\right)}{\left(\sqrt{3}-1\right)\left(\sqrt{3}+1\right)}+\frac{\sqrt{5}\left(\sqrt{7}-\sqrt{3}\right)}{\sqrt{5}}-\sqrt{28}\)
\(=\frac{2\sqrt{3}}{3-1}+\sqrt{7}-\sqrt{3}-2\sqrt{7}\)
\(=\sqrt{3}+\sqrt{7}-\sqrt{3}-2\sqrt{7}\)
\(=-\sqrt{7}\)