Question

vă rog,am nevoie re răspuns repede,dau coroana!​

Answer 1

Răspuns:

$6 \sqrt{7} - 9 \sqrt{3} - 6 \sqrt{7 } = \\ = - 9 \sqrt{3}$

Answer 2

 

$\displaystyle\bf\\3\cdot \Big(2\sqrt{7}-3\sqrt{3}\Big)-\sqrt{252}=\\\\=6\sqrt{7}-9\sqrt{3}-\sqrt{36\times7}=\\\\=\underline{6\sqrt{7}}-9\sqrt{3}-\underline{6\sqrt{7}}=\boxed{\bf-9\sqrt{3}}$