tolong di jawab ya besok dikumpulkan

1. 5^-x-y = 1/625
5^-x-y=5^-4
-x-y=-4
x+y=4
2. 2√48+√12-√75
8√3+2√3-5√3=5√3
3. 3√5(2√2+√5)=6√10+15
4. (√7+√3)(√7-√3)=7-√21+√21-3
=7-3=4
5. 4/√2 X √2/√2 = 4√2/2 = 2√2