(с+d)²

To simplify the expression (c + d)², we can use the formula for squaring a binomial, which is (a + b)² = a² + 2ab + b².

In this case, we have (c + d)², so we can substitute c for a and d for b in the formula:

(c + d)² = c² + 2cd + d²

Therefore, (c + d)² simplifies to c² + 2cd + d².