Answer:
-3√5 + 10√3
Step-by-step explanation:
Let's start by reducing √20, √45 and √12:
√20 = √4√5 = 2√5
√45 = √9√5 = 3√5
√12 = √4√3 = 2√3
Then the original expression 3√20 - 3√45 becomes:
3 { (2)√5 - 3√5 } , or 3 {-1√5}
Now add in that 5√12, in simplified form from the work we did above:
5(2)√3, or 10√3
The final answer, obtained from combining the three given terms, is
-3√5 + 10√3. This cannot be simplfied further.