The sum of three different numbers is 18. if every number is a prime number, what are the three numbers?

Hi my sisters and brothers can tell me the answer because i don’t understand the question

For what values of the variable x is the expression square root of 7x+14+ square root of 7-x a real number?

Afamily has five members. a mom, a dad, two sisters, & a brother. the family lines up single file. what is the probabillity that the mom is at the front of the line