Question

Find the difference: 20-√80
O-12√5
O-2√5
02√5
O-2√15

Answer 1

The difference between 20 and √80 is found by simplifying √80 to 4√5 and then subtracting this from 20, resulting in the expression 20 - 4√5, which cannot be simplified further.

Step-by-step explanation:

To find the difference 20 - √80, we need to simplify √80 first. √80 is equivalent to √(16 × 5) which simplifies to 4√5 because √16 is 4. Now, we subtract 4√5 from 20 to find the difference.

20 - 4√5 = 20 - (√16√5) = 20 - (4√5) = 20 - 4√5.

This cannot be simplified further as 20 is not under a square root and doesn't have the same radical part as √5. Therefore, the correct answer is 20 - 4√5.

Answer 2

Step-by-step explanation:

maybe you missed something in the problem definition or in the answer options, but the answer options do not contain any right answer to the described problem.

20 - sqrt(80) = 20 - sqrt(16×5) = 20 - 4×sqrt(5) =

= 11.05572809...

it is simple to estimate, in what dimension the result should be : 80 is very close to 81. so the sqrt(80) is also very close to the sqrt(81), which is 9.

20 - 9 = 11.

so, all the negative answer options are wrong by default.

and the only positive one is 2×sqrt(5) = 4.472135955...

additional thoughts :

20 = 4×5 or 4×sqrt(5)×sqrt(5)

so, we could write the problem as

4×sqrt(5)×sqrt(5) - 4×sqrt(5)

which could be simplified to either

4×sqrt(5)×(sqrt(5) - 1)

or

4×(5 - sqrt(5))