Step-by-step explanation:
4√2 . √2
= 4 * 2
= 8
3√7 - 2√7
= √7 ( 3 - 2 )
= √7 ( 1 )
= √7
√7 / 2√7 = 1 / 2
2√5 . 2√5
= 2 * 2 . √5 *√5
= 4 * 5
= 20