Why is it important to solve an equation for a specific variable

What is the value of f(x) = 2.2 for f(-2)?

Adistribution has the five-number summary shown below. what is the third quartile, q3, of this distribution? 22, 34, 41, 55, 62

The party planning committee has to determine the number of tables needed for an upcoming event. if a square table can fit 8 people and a round table can fit 6 people, the equation 150 = 8x + 6y represents the number of each type of table needed for 150 people.