1) ( √12 - 2√18 ) * √2
First, simplify inside the parentheses:
√12 = 2√3
√18 = 3√2

Now substitute these values back into the expression:
( 2√3 - 23√2 ) √2
( 2√3 - 6√2 ) * √2

Now distribute the √2:
2√3√2 - 6√2√2
2√6 - 6*2
2√6 - 12

Therefore, ( √12 - 2√18 ) * √2 simplifies to 2√6 - 12.

2) ( √15 - √20 ) * √5
First, simplify inside the parentheses:
√15 cannot be simplified further
√20 = 2√5

Now substitute these values back into the expression:
( √15 - 2√5 ) * √5

Now distribute the √5:
√15√5 - 2√5√5
√75 - 2*5
√75 - 10

Therefore, ( √15 - √20 ) * √5 simplifies to √75 - 10.