Jika akar 20 + 3 akar 5 + akar 45 =

√20 +3√5 +√45
=√4×5 + 3√5 + √9×5
=2√5 + 3√5 + 3√5
=8√5

√20 + 3√5 + √45
= √4.5 +3√5 + √9.5
= 2√5 + 3√5 + 3√5
= 8√5