algebra 2 help combining and simplifying?

Question

√25
------ the whole problem is under the square root
128




2√20+ 8√45 - √80

(how would i combine and simplify this.)

and
(3√y)^2

Answer 1

Simplify:

√(25/128) = √[2*25/(2*128)] = √[2*5²/(256)]
= √[2*5²/(16²)] = 5√2 / 16
_______

2√20 + 8√45 - √80 = 2√(4*5) + 8√(5*9) - √(5*16)
= 2*2√5 + 8*3√5 - 4√5 = 4√5 + 24√5 - 4√5 = 24√5
_______

(3√y)² = 9y