What does semicolon mean in math

Write an expression that has three terms and simplifies to 4x - 7. identify the coefficient(s) and constant(s) in your expression

One line passes through (-7,-4) and (5,4) . another line passes through the point (-4,6) and (6,-9)

Aclassroom is made up of 11 boys and 14 girls. the teacher has four main classroom responsibilities that she wants to hand out to four different students (one for each of the four students). if the teacher chooses 4 of the students at random, then what is the probability that the four students chosen to complete the responsibilities will be all boys?