√4*√7- 2√2a 2√7-2√2a 2(√7-√2a) =____________=_______________= __________________=
5((√2a)²-(√7)²) 5(√2a-√7)(√2a+√7) 5(√2a+√7) ( √2a-√7)
2
=_________
-5(√2a+√7