Tolong bantuin soal pleaseeeeee

√45+√245-√20-√405 =
√9x5 + √49x5 - √4x5 - √81x5
3√5 + 7√5 - 2√5 - 9√5
= -√5

√40:√5 =
√8
√4x2
= 2√2

√6(3√8+√32) =
√6 (3√4x2 + √16x2)
√6 (3x2√2 + 4√2)
√6 (6√2 + 4√2)
√6 (10√2)
10√2 x √6
10√12
10√4x3
10x2√3
= 20√3