原式=(5√2)²-(3√5)²
=50-45
=5
2. 原式=(√5)²-(√3)²-(√6+√2)²
=5-3+(√6)²-2√6*√2-(√2)²
=2+6-4√3-2
=6-4√3
3. 原式=(9√2+5√2/5-2√2)/4√2
=8√2/4√2
=2
原式=(5√2)²-(3√5)²
=50-45
=5
2. 原式=(√5)²-(√3)²-(√6+√2)²
=5-3+(√6)²-2√6*√2-(√2)²
=2+6-4√3-2
=6-4√3
3. 原式=(9√2+5√2/5-2√2)/4√2
=8√2/4√2
=2