Add 31−−√+31−−√ .

To add √31 + √31, you would combine the terms with the same radicals. Since the two terms have the same radical (√31), you can add their coefficients:

1√31 + 1√31 = 2√31

Therefore, 31−−√ + 31−−√ = 2√31.

To add 31-√+31-√, first find the values of each square root separately.

Starting with the first square root: √31.

Since 31 is not a perfect square, we can't simplify the square root any further.

Now, let's solve the second square root: √31.

Again, since 31 is not a perfect square, we can't simplify the square root.

Next, add the two square roots together: √31 + √31.

This is equivalent to 2√31.

So, the sum of 31-√ + 31-√ is 2√31.

To add two square roots, we need to simplify each square root individually and then combine them.

Let's simplify each square root first:

√31 = 5.57 (approximately)

Now, let's add the two simplified square roots:

5.57 + 5.57 = 11.14

So, the sum of 31−−√+31−−√ is approximately 11.14.