Match each scenario with the object that will have the greatest gravitational force in that scenario {HELP ITS DUEEE}

Evaluate the expression for the given value of the variable 7a - 4a for a =8

Give the equations of two different lines that are perpendicular to the line 3x + 4y = 7.

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?