Forming equations using proportion by Boxed Rockets

Form Equations to Represent the Following

Question 1:

y is directly proportional to x, when x = 12, y = 48

y = 4 x

Question 2:

y is inversely proportional to x, when x = 7, y = 2

y = \frac{14}{x}

Question 3:

y is directly proportional to x, when x = 8, y = 16

y = 2 x

Question 4:

y is directly proportional to x, when x = 4, y = 40

y = 10 x