3sqrt2xx5sqrt103√2×5√10
=(3xx5)sqrt2xxsqrt10--(1)=(3×5)√2×√10−−(1)
=15sqrt(2xx10)=15√2×10
=15sqrt20=15√20
=15sqrt(4xx5)=15√4×5
15xxsqrt4xxsqrt515×√4×√5
15xx2xxsqrt515×2×√5
30sqrt530√5
at stage (1)(1) you could do
(3xx5)sqrt2xxsqrt(2xx5)(3×5)√2×√2×5
=15sqrt2sqrt2sqrt5=15√2√2√5
=15xx2sqrt5=30sqrt5=15×2√5=30√5