Find the value of x. Please help

Three times the difference of federico’s age, and 4, increased by 7, is greater than 37. what are possible values of federico’s age?

1- what do you think the product of a nonzero rational number and an irrational number is? is it rational or irrational? make use of variables, the closure property of integers, and possibly a proof by contradiction to prove your hypothesis.2- why do we have to specify that the rational number must be nonzero when we determine what the product of a nonzero rational number and an irrational number is? if the rational number were 0, would it give us the same result we found in the first question?

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