3²+4²+7²

To find the solution to this expression, first calculate the squares of each number:

3² = 3 * 3 = 9 4² = 4 * 4 = 16 7² = 7 * 7 = 49

Next, add these three values together:

9 + 16 + 49 = 74

Therefore, the solution to the expression 3² + 4² + 7² is 74.