Write an equation for line through (4,9), m=-9

Two variables, x and y, vary inversely, and x=12 when y=4. what is the value of y when x=3?

Which system of linear inequalities is represented by the graph?

The area of a rectangle is 10 cm^2. one side of the rectangle is x cm. express the perimeter of the rectangle in terms of x and show that this rectangle cannot have a perimeter of 12 cm. the perimeter of the rectangle in terms of x is __ cm