The square of 18 is 324 and the square of 15 is 225.

324+225=549 This is either that you decompose 549 into prime factors.

549=3* 183=3*3*63=3*3*9*7=3*3*3*3*7

Look, there are two identical numbers in the decomposition formula, so the square root puts forward one.

In other words, 549 roots are 9 times as many as the root number 7.

Another example is 341=11* 31.Because there is no same number, it is impossible to make a prescription.