Jawabanmu

2014-02-21T06:37:34+07:00
2(25 + 20 √5 + 20) = 2(45 + 20 √5) = 90 + 40 √5
2014-02-21T06:42:55+07:00
2(5+2√5)²
= 2(5+ √20)²
=2(5²+√20²)
=2(25+20)
=2(45)
=90