Final answer:
A linear function is a mathematical function that can be represented by a straight line. In this case, z is a linear function of x and y with a slope of 7, which means that the change in z is directly proportional to the changes in x and y.
Step-by-step explanation:
A linear function is a mathematical function that can be represented by a straight line. In this case, you are given that z is a linear function of x and y with a slope of 7. This means that the change in z is directly proportional to the changes in x and y. You can express this relationship using the equation z = 7x + 7z