Idon’t understand why it has 3 numbers when there is only supposed to be 2

Find the solution of this system of equation -7x+y=-20 9x-3y=36

One positive integer is 2 less than another. the product of the two integers is 24. what are the integers

Amayoral candidate would like to know her residents’ views on a public open space before the mayoral debates. she asks only the people in her office. her co-workers are an example of a census population convenience sample simple random sample