Abox of 6 golf balls costs $7.32. at that rate, how much will a box of 15 golf balls cost?

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

I’ve been trying all day to figure this puzzle out. i need the work for it aswell. it is a factoring polynomials tarsia. the image is below.

Whit h equation best represents this situation the number 98 increased by an unknown number equal to 120