Can someone work these and show the work?

The variable z is directly proportional to x, and inversely proportional to y. when x is 4 and y is 13, z has the value 1.2307692307692. what is the value of z when x= 9, and y= 20

Answer the questions in the attachment. a rescue helicopter is at point a and a rescue boat is at point e. the helicopter pilot spots boats in distress at points d and c,with angles as marked in the diagram. figure abce is a rectangle. the altitude of the rescue helicopter, represented by ae, is 5000 feet.

Solve this system of equations. 12x − 18y = 27 4x − 6y = 10