simplify (square5)(square2)

I don't know if you mean square root, or square.

Here is square:
5^2 * 2^2= 25*4 =100

How about (square5)(square2) = square(5*2) ?

To simplify (square5)(square2), we need to understand whether "square" refers to squaring a number (raising it to the power of 2) or taking the square root of a number.

If "square" refers to squaring a number, we can simplify it as follows:
5^2 * 2^2 = 25 * 4 = 100.

If "square" refers to taking the square root of a number, we can simplify it as follows:
(square5)(square2) = square(5*2) = square(10), which means taking the square root of 10.

Please clarify whether you meant squaring a number or taking the square root, so that I can provide you with a more accurate answer.