Help asap, please!!..

Mrs. morton has a special reward system for her class. when all her students behave well, she rewards them by putting 3 marbles into a marble jar. when the jar has 100 or more marbles, the students have a party. right now, the the jar has 24 marbles. how could mrs. morton reward the class in order for the students to have a party?

Three times the sum of a number and seven is negative thirty-six. what is the number?

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