What is the input of the function when the output is 20?

What two numbers have a sum of 217 and difference of 85?

A clerical worker takes 2 times as long to finish a job as it does an executive secretary. Working together, it takes them 5 hours to finish the job. How long would it take the clerical worker, working alone, to finish the job?

Ten years ago, the age of Mark was half of Mary’s age. If the ratio of their present age is 3:4, what will be the total of their present age?

Solve the system of equations.

​-7 + y = (6/5)x
-9x - 5y = 40

A high school is having a talent contest and will give different prizes for the best 5 acts in the show. First place wins the most money, and each place after that wins 50 less than the previous place. Create a model that can be used to determine the total amount of prize money based on the value of the first place.

What two numbers multiply to -60 & add to -4?

Find two consecutive even integers with a product of 224.

​The sum of two numbers is 40. The larger number is 20 more than the smaller number. What are the two numbers?

Six times a number is 16 more than two times the number.  What is the number?