Factorise h2+2hk+k2 completely.

The expression h^2 + 2hk + k^2 can be factorised as follows:

Step 1: Identify the expression as a perfect square trinomial. A perfect square trinomial is a trinomial that is the square of a binomial. In this case, the trinomial is a perfect square because the first term (h^2) is the square of h, the last term (k^2) is the square of k, and the middle term (2hk) is twice the product of h and k.

Step 2: Write the expression as a square of a binomial. The binomial is the square root of the first term plus the square root of the last term, which is (h + k). Therefore, the expression h^2 + 2hk + k^2 can be factorised as (h + k)^2.