Jawabanmu

2014-08-30T19:20:46+07:00
√20=√4×5= 2√5
√80=√16×5=4√5
2014-08-30T19:21:26+07:00
√20 = √4 x 5
 = √2² x 5
 = 2√5
√80 = √16 x 5
 = √4² x 5
 = 4√5
kalo dijumlah 
4√5 + 2√5 = 6√5